TEE ATISE 

OK 

PHOTOGRAPHY, 

BY 

CHARLES  WA  LDACK. 


FOURTH  E  D I T i 0  H - 


C  I  N  C  I/N  N  A  T  t  : 
HJ  W;t        punier,  No.  60  West  Thiku  Street. 
1865. 


Hi 


\ 


Digitized  by  the  Internet  Archive 
in  2014 


1 


https://archive.org/details/treatiseonphotogOOwald_0 


WILLARD  &  CO. 

PHOTOGRAPHIC  WAREHOUSE, 

No.  522  Idfcvositl  way  , 

NEW  YORK. 

§toufactwm&  Jmpavtcts,  and  grains. 


AGENT8  FOR 

REYNOLDS'  PATENT  CAMERA  ATTACHMENT, 

For  Making  the  Celebrated  Porcelain  Piotnr^s; 

ALSO,  FOE  THE  BEST  QUALITY  OF 

PORCELAIN  G-3L.A.SS- 

MANUFACTURERS  OF 

DAGUERREOTYPE  CASES 

IN  GREAT   VABIE T  Y  • 

lyillard's  Opal  Varuish, 

}Villard>s  Union  Gilding, 

Willard's  Union  Collodion, 

Willard's  Gem  Cameras, 

Willard's  Focussing  Glasses. 

GILT  AND  ROSEWOOD  FRAMES  OF  EVERT  DESCRIPTION. 

Cameras,  Apparatus,  Mattings,  Preservers,  Pure  Chemicals,  eta. 

pur  Stock  is  always  large,  and  will  be  sold  at  all  times  at  the  lowest 
C^SK  PRICES. 

WILLARD  &  CO., 

JVo,  §22  Broadway,  JT.  F. 


3* 

8 


3 

I 
•8 

i 


PC 
w 

-a! 
u 

Q 

Q 

25 

1  U3 


o 


PC 

oc 
2 


P 

o 
o 

w 

< 
O  0 

o 


0 

H 

H 
h 

H 

o 
® 
'A 
P 


pas. 


OC  ** 

LU  a 

Q-  7 

Cu  g. 


CD  " 

—J  o 


1   © 

<C  * 

LU  ^ 

—J  £ 

LU  i 


g  1 


8* 

1 

w 


© 

O 
.© 


© 


sr 


s 

*- 
»- 

03 


CO 

< 
< 

Cu 
CL 
< 

a 


> 
< 

CO 


O  B 


C5 


CC  g 

w 
.J 
.J 
-1 

CO  ° 


co  3 

<  * 

55 

CO  ° 

DC 
O 

u. 


Ui 

< 


g 

Ph 
P* 

*  t 

*  I 

£3  " 

w  _ 

►  1 

3  3 


CO 


&3 
o 


EH 


Pi 

CO 

a 

P5 

►-5 

i=> 
o 

B 


O 
h3 


O 
t— i 
Eh 

Ph 
Ph 


g  H 

a  ;H 

H 
< 

P 
H 

h 

H 

hi 

P 
Gf 


•■g 


EDW.  AND  H.  T.  ANTHONY  &  CO. 

JVb.  501  Broadivay,  New  York, 


MATERIALS  OF  EVERY  DESCRIPTION. 

ward',  Solar  Camera;  At  Js  Sw  *a£1  f * <Wm »  Wood- 
Notes;"  The  "London  PhotoVraI-    t  Sutton's  "Photographic 

Plate-Vice.  "otograplne  News;"  Pearsell's  Patent  Universal 

MANUI'ACTUREKS  OP 

AnTrs  FIint  v-i9h  *» 

noteraek;  Anthony's  Neg.™i %  q[^T L f  ,7*  P*"*  Varni*,  that  will 
Anthony's  Pure  Iodides  afd  B  om  r  Wh„  ^  Albumenized  *»P«  i 
Chloride  of  Gold;  Anthony"  Wo  r,,t  /  s/N'trateof  Silver ;  Anthony's 
Double  Sulphate  ron  and  A™  2  n  , '  1  °f  fiSodium'  Ace(««  of  Soda, 
Instantaneous  Stereoscopic  V~ fi"efCfhemi^  Anthony's 
Anthony's  Gilt  Frames  ^tho  y^s^^t  *  CardS: 

graphic  Albums.  victualed  Collod.on  ;  Anthony's  Photo- 

Th<>,,      .    „  IMPOIITER8  OF 

-the  Genuine  Saxe  and  Rive  Finer  k-t.  o. 

atives,  the  Best  French C^^l^^™"0^01™  for  N<*- 
Fancy  Frames,  Bristol  Board,  Tte  *  ^  Passe-p«touts, 

Celebrities,  Albums,  etc.  fe<e:eoseop,c  V.ewe,  Cartes  de  Visite  of 

„,    „  ,  i>  EA  i/ioum  in 

Glass  Baths  and  Pans,  Apparatus,  Mnttings,  Preservers  p.,...  a,„  „ 

Photographic  Backgrounds,  Fancy,  Plain,  or  Landscape. 

MICROSClpi°^AMERAs. 

EDW.  AND  H.  tTaNTHONY  &  CO. 
Nl®,  5Qf  Broadway* 
MANUFACTURERS  OF  PHOTOGRAPHIC  ALBUMS. 


THCE  CELEBRATED 

HELION  COTTON. 


The  Helion  Cotton  is  made  by  the  DAGUERRE  MANUFACTURING 
COMPANY  exclusively,  from  the  best  Sea  Island  staple,  by  a  process  unknown 
to  all  other  chemists  in  the  world. 

The  Helion  Cotton  is  adapted  to  every  structure  of  light  and  condition 
of  circumstances,  and  is  exclusively  used  by  all  first-class  Photographers  in 
America,  and  has  not  been  condemned  by  a  living  soul  since  the  discovery  of 
the  present  mode  of  making  it. 

The  Helion  Cotton  is  made  with  three  distinct  grades  of  intensity, 
numbering  1,  2,  and  3.  No.  1  indicates  the  greatest  degree  of  intensity,  and 
is  well  adapted  to  high  soft  lights.  No.  2  is  less  intense  than  No.  1,  and  No.  3 
has  the  least  intensity.  In  collodion  it  flows  free  and  smooth  as  the  glass 
itself,  and  the  three  grades  may  be  mixed  so  as  to  produce  any  required 
results. 

FORMULA  FOR  MAKING  COLLODION  WITH  THE  HELION  COTTON. 

95  per  cent.  Alcohol  and  Con.  Ether,  equal  parts. 

5  grains  to  the  ounce  Iodide  of  Ammonium  or  Cadmium. 

2%  grains  to  the  ounce  Bromide  of  Cadmium  or  Potassium. 

5  to  6  grains  to  the  ounce  Helion  Cotton. 
N.  B. — Iodize  before  adding  the  Cotton.    Before  flowing,  add  to  each  ounce  of 
Collodion  three  to  five  drops  of  full  strength  Tincture  of  Iodine.    Tincture  of  Iodine 
ia  made  by  dissolving  Crystals  of  Dry  Iodine  in  Alcohol. 

PRICE  OF  HELION  COTTON. 

No.  1  $1  00  per  ounce.   No.  2  $1  00  per  ounce.   No.  3  75  cts.  per  oz. 

FOR  SALE  AT  THE  FOLLOWING  ESTABLISHMENTS. 

Willard  &  Co.,  Holmes,  Booth  &  Hayden,  Scovill  Manufacturing  Co.,  Will- 
cox,  Rogers  &  Graves,  R.  V.  Harnett,  W.  H.  Mountfort,  Genert  Bros.,  J.  F. 
Luhme  &  Co.,  George  A.  Chapman,  New  York;  Benjamin  French,  John  Saw- 
yer, Boston,  Mass. ;  Parsons  &  Green,  Albany,  N.  Y. ;  L.  C.  Everett,  Troy, 
N.  Y. ;  J.  A.  Hall  &  Co.,  Utica,  N.  Y. ;  F.  Hendricks,  Syracuse,  N.  Y. ;  R.  B. 
Appleby,  Rochester,  N.  Y. ;  R.  O.  Benton,  Buffalo,  N.  Y. ;  C.  C.  Kelsey,  Cin- 
cinnati, O. ;  R.  B.  Appleby,  Chicago,  111. ;  E.  M.  Osborn,  Washington,  D.  C. ; 
William  Shew,  San  Francisco,  Cal. ;  George  Dabbs  &  Co.,  Philadelphia,  Pa. ; 
W.  H.  Tilford,  St.  Louis,  Mo. 

SPECIALTY*— We  desire  to  call  the  attention  of  Photographers  and  Dealers  in 
photographic  cotton  to  this  fact,  that  Helion  Cotton,  Collodion,  and  Chloride  of  Gold,  are 
specialities  with  us.  We  make  but  those  three  articles,  all  of  which  we  know  are  as 
good  and  as  cheap  as  the  market  affords. 

Beware  of  impositions.  The  unprecedented  popularity  of  the  Helion  Cotton  has  in- 
duced others  to  imitate  our  boxes  in  size  and  style.  Buy  of  regular  agents,  and  you  will 
get  the  genuine  article. 

READ  THE  FOLLOWING  RECOMMENDATIONS. 

Dear  Sir:  Your  No.  1  Helion  Cotton  is  No.  1  in  every  respect.  Send  us  a  few  mor« 
pounds  at  your  earliest  convenience.  MOSES  SUTTON,  Detroit,  Mich. 

Dear  Sir:  Something  more  than  one  year  ago  we  commenced  using  your  Helion  Cotton, 
and  have  used  it  ever  since,  with  the  most  gratifying  results.  We  have  no  hesitation  in 
recommending  it  to  all,  as  the  most  reliable  photographic  cotton  in  the  market. 

J.  GURNEY  &  SON,  New  York. 

Dear  Sir:  We  have  used  your  Helion  Cotton  for  a  long  time,  and  have  found  it  uni- 
formly good.  We  have  no  hesitation  in  recommending  it  as  the  best  photographic  cotton 
we  have  used.  C.  D.  FREDERICKS  &  CO.,  New  York. 

Dear  Sir:  We  have  used  your  Helion  Cotton  long  enough  to  satisfy  us  that  it  is  uni- 
formly good.  M.  B.  BRADY,  New  York. 

Dear  Sir :  Your  No.  3  Helion  Cotton  is  most  admirably  adapted  to  our  structure  of  light. 
It  gives  sufficient  strength  to  our  negatives  without  redeveloping,  and  is,  in  all  respects, 
the  most  uniform  and  the  best  we  have  ever  used.  A.  BOGARDUS,  New  York. 

DAGUERRE  MANUFACTURING  CO. 

P,  D,  T,  DAVIE,  Chemist.  93  Crosby  Street,  New  York. 


THE  "OLD  RELIABLE" 


P.  SMITH  &  CO. 

( LATE  PETER  SMITH,) 

JVb.  36  West  Fifth  Street,  Cincinnati,  Ohio, 
Now  keep  on  hand  a  full  and  complete  assortment  of  Goods  in  our  line,  comprising 

CAMERAS,  APPARATUS,  MATTINGS, 

Preservers,  Plates,  fancy  Frames,  Cases,  etc,  Photographic  Paper,  Chemicals, 

AND  MATERIALS  OF  EVERY  DESCRIPTION  FOR 

mw  km 


Our  Assortment  is  Large,  and  will  be  kept  up. 

THE  CHEMICALS 

ARE  FROM  THE  BEST  LABORATORIES,  AND  ARE  SELECTED  WITH  THE  GREATEST  CASE. 

ALL  ORDERS  WILL  BE  PROMPTLY  FILLED, 

—  AND  — 

GOODS   SOLD  AT   TJIE   LOWEST  PRICES. 


OUR  TERMS  ARE  CASH,  OR  COLLECT  ON  DELIVERY. 

Your  Orders  are  kindly  solicited,  and  satisfaction  guaranteed.  Orders 
should  be  written  plainly,  and  the  name  of  the  place,  County,  and  State 
given.   All  orders  should  be  addressed 

P.   SMITH  &  CO., 

No.  36  West  Fifth  Street, 

CINCINNATI,  OHIO. 


CINCINNATI  STOCK  DEPOT. 


C.  C.  KELSEY, 

WHOLESALE  DEALER  IN 

PHOTOGRAPHIC  GOODS, 

MANUFACTUKEE  OF  THE  CELEBRATED 

B&aaer  doIMtoa,  Baaaer  f&ratsa, 

ALBUMENIZEO  PAPER,  CHLORIDE  OF  GOLD,  ETC., 

No.  137  West  Fourth  Street,  Cincinnati,  Ohio. 


ARTISTS  AND  AMATEURS  IN  PHOTOGRAPHY 

WILL  FIND  AT  THIS  ESTABLISHMENT  THE   LARGEST   AND  M08T   COMPLETE  ASSOttT- 

MENT  IN  THE  WEST,  COMPRISING 

Cameras  of  every  make, 

Apparatus  of  all  kinds, 

Cases,  Plates,  and  Mats, 
Superior  French  and 

English  Negative  Glass, 

Plain  and  Fancy  Backgrounds, 

Pure  Photographic  Chemicals, 
Atwood's  Patent  Alcohol, 
Photographic  Presses, 
Preservers, 

Solar  Cameras, 
AND  ALL  OTHEK  ARTICLES  USED  IN  THE  ART. 

THE  LARGEST  AND   MOST  ELEGANT  ASSORTMENT  OF 

PHOTOGRAPHIC  ALBUMS 

 AND  

OYAL  FRAMES 
In  the  West,  at  Unusual  Low  Prices. 
Card  Mounts,  printed  in  elegant  style,  at  lower  rates  than  can  be  done  at  any 
any  other  House. 
Special  attention  given  to  refining  Artists'  Wastes. 

None  but  the  best  Stock  kept.  Orders  attended  to  immediately.  Prices 
always  as  low  as  any  in  the  trade. 

TERMS— Cash,  or  Collect  on  Delivery. 

Address  Orders 

O.  O.  KELSEY, 

137  West  Fourth  Street,  Oinoinnati,  0. 


C.  S.  RUSSELL, 

SUCCESSOR  TO 

EDWARD  MEAD  &  CO. 

Comer  Fifth  and  Olive  Streets, 
ST.  LOUIS. 


THE  SPECIAL  ATTEITTIOIT  OE 

PHOTOGRAPHIC  ARTISTS 

IS  CALLED  TO  THE  ABOVE  CARD  OF  A  HOUSE  WHICH  HAS  BEEN  CON- 
NECTED WITH  THIS  BUSINESS  FOR  MORE  THAN  TWENTY  YEARS 
PAST,  AN  EXPERIENCE  WHICH  ENABLES  IT  TO 

FURNISH  THE  OPERATOR  WITH  THE  BEST  QUALITY  OF 

CAMERAS, 

APPARATUS, 

CHEMICALS, 

FRAMES, 

PLATES, 

CASES, 

GLASS, 

Etc.,  Etc. 

AT  THE  LOWEST  MARKET  PRICES. 


^The  reputation  which  this  House  has  already  earned 
itself  in  the  past,  for  the  prompt  and  honest  man- 
ner in  which  it  has  filled  all  orders  intrusted  to  it, 
will,  it  is  hoped,  recommend  it  to  those  who  may  not 
have  yet  favored  it  with  their  patronage. 


TILFORD'S 

ST.  LOUIS  JIOTOGRAWJTOCK  DEPOT. 

ESTABLISHED  1848. 


"W.  H.  TILFOBD, 


IMPORTER  OF  AND  DEALER  IN 


CHEMICALS,  APPARATUS,  CAMERAS,  CASES,  FRAMES,  ETC.,  PHOTOGRAPH  ALBUMS,  AND, 
ALL  ARTICLES  AND  APPARATUS  APPERTAINING  TO 


STTN"  PIOTUEES, 

Bo.  17  North  Fourth  Street,  Opposite  Oourt-House,  St.  Louis, 

Having  just  completed  and  removed  to  my  new  building,  especially  arranged 
and  adapted  to  Photographic  Materials,  I  am  now  prepared  to  offer  the  most 
extensive  and  varied  assortment  of  the  above-named  Goods  out  of  New  York. 
My  practical  and  long  experience,  together  with  advantages  of  purchasing  i$ 
large  quantities,  for  cash,  of  the  best  Factories,  enables  me  to  furnish  my 
customers  with  reliable  Goods,  at  low  rates,  and  with  promptness. 

W.  DEC.  TILFOBD, 
No.  17  North  Fourth  Street,  Opposite  Court-House,  St.  £oui»,  Mo; 


TEEATISE 


ON 


PHOTOGRAPHY. 


BY 


CHARLES  WALDAOK. 


POURTH  EDITION. 


CINCINNATI: 
H.  Watkin,  Printer,  No.  60  Third  St.,  kbar  Walnut. 
1865. 


Entered  according  to  Act  of  Congress,  in  the  year  1865,  by 
CHAS.  WALDACK, 
In  the  Clerk's  Office  of  the  District  Court  of  the  United  States  for  the  Soitthen 
District  of  Ohio. 


PREFACE 


Numerous  changes  have  been  made  in  this  edition. 
Matters  become  obsolete  have  been  suppressed,  and 
improvements  in  the  processes  generally  practiced  have 
been  described.  We  have  not  noticed,  however,  any 
of  the  new  processes  in  printing,  which  have  lately 
made  their  appearance.  The  processes  of  carbon  print- 
ing we  consider  not  yet  sufficiently  practical  to  be  of 
use  to  the  professional  photographer.  We  thought  of 
being  able  to  give  a  method  superior  to  the  ordinary 
printing  process,  and  even,  on  this  account,  retarded 
the  publication  of  this  edition;  but  the  process  in 
question  turned  out  to  have  been  greatly  overrated. 
We  refer  here  to  the  Wothlotype  process,  the  appear- 
ance of  which  created  such  an  excitement  in  the  pho- 
tographic community.  The  results  obtained  by  this 
process  do  not  meet  the  anticipation  of  photographers. 
Prints  made  by  it  possess  no  advantage  over  those 
made  in  the  ordinary  way,  neither  in  quality,  facility 
of  manipulation,  cost,  nor  permanency.  Our  aim  being 
to  bring  forth  a  guide  for  practical  photographers,  we 
have  thus  omitted  a  description  of  it,  and  devoted  our 
space  to  objects  of  more  direct  value. 


1 

CONTENTS. 


CHAPTER  pagk 

I.    History  of  Photography   9 

II.  Philosophy  of  Light — Decomposition  of  Light — 
Its  Illuminating,  Heat-producing,  and  Actin- 
ic Properties — Invisible  Rays — Refraction — 

Lenses — The  Photographic  Camera   16 

III.  General  Theory  of  the  Collodion  Process   23 

IV.  On  the  different  Compounds  used  in  the  produc- 

tion of  Collodion  Pictures   26 

V.    On  positive  Collodion  Pictures   27 

VI.    On  Collodion   29 

VII.    The  Silver  Solution  for  Positives   59 

VIII.    Developing  Solution  for  Positives   69 

IX.    The  Fixing  Solution   73 

X.    Cleaning  the  Plate   75 

XI.    Formation  of  the  Film  of  Collodio-Iodide  of 

Silver   78 

XII.    Exposure  in  the  Camera   190 

XIII.  Development  of  the  Picture   192 

XIV.  Fixing  the  Picture   197 

XV.    Mounting  the  Picture   198 

XVI.    On  Collodion  Negatives   101 

XVII.    Collodion  for  Negatives   103 

XVIII.    The  Silver  Solution  for  Negatives   107 

XIX.    The  Developing  Solution  for  Negatives   109 

XX.    The  Fixing  Solution   Ill 

XXI.    Practical  Details  of  the  Negative  Process   112 

XXII.    Strengthening  of  the  Negative   117 

XXIII.  Alcoholic  Collodion   122 

XXIV.  Imperfections  in  Collodion  Photographs   123 


Vi  CONTENTS. 

CHAPTER  pag* 

XXV.    Positives  on  Paper   134 

XXVI.    Direct  Positive  Process   136 

XXVII.    Preparation  of  the  Sensitive  Paper   140 

XXVIII.    The  Printing   153 

XXIX.    Toning,  Fixing,  Washing,  and  Mounting  of  the 

Prints  ,.....«:   156 

XXX.  On  the  Fading  of  Positive  Prints   168 

XXXI.  Instruments  Used  for  Making  Enlarged  Prints 

from  Collodion  Negatives — The  Solar  Camera  172 
XXXII.    Enlarged  Prints  by  the  Direct  Positive  Process...  177 

XXXIII.  Enlarged  Prints  by  the  Developing  Process   179 

XXXIV.  Preserved  and  Dry  Collodion  Processes   193 

XXXV.    The  Tannin  Process   196 

XXXVI.    The  Tannin  and  Honey  Process   208 

XXXVII.    The  Collodio-Albumen  Process   210 

XXXVIII.    On  Rapid  Dry  Collodion  Plates   213 

XXXIX.    On  Copying   215 

XL.    Out-door  Photography   222 

XLI.    Instantaneous  Photography   231 

XLII.    Photography  on  Painter's  Canvas   235 

XLIII.    Binocular  Vision — the  Stereoscope — How  to  take 

Stereoscopic  Pictures   242 

XLIV.    Transparent  Positives— The  Opaltype — Enlarg- 
ing Negatives   247 

XLV.    Recovery  of  Silver  from  old  Solutions,  Paper 

Clippings,  Washings,  etc   251 

XLVI.    Removing  Stains  from  the  Skin,  Linen,  etc   256 


TREATISE  ON  PHOTOGRAPHY. 


CHAPTER  I. 

History  of  Photography. 

The  art  of  photography  (from  the  Greek 
light,  and  print,)  includes  all  pro- 

cesses by  which  images  or  impressions  are 
obtained  through  the  agency  of  light.  The 
application  of  the  action  of  light  to  this  pur- 
pose is  but  of  recent  introduction. 

The  ancients  do  not  seem  to  have  directed 
their  attention  to  the  modifications  brought  on 
by  light,  in  the  physical  and  chemical  condi- 
tions of  certain  bodies.  The  only  phenomenon 
recorded  by  them  is  the  loss  of  brilliancy  of 
certain  precious  stones,  such  as  opal  and 
amethyst,  by  a  prolonged  exposure  to  the 
sun's  rays.  In  the  middle  ages  some  of  the 
alchemists  noticed  the  fact  that  the  fused  chlo- 
ride of  silver,  called  by  them  horn  silver  or 
horn  moon,  blackened  under  the  influence  of 
light. 

In  1722,  Petit  remarked  that  certain  salts, 
such  as  the  nitre  and  sal  ammonia,  crystal- 
ized  easier  being  exposed  to  -the  light. 

In  1765,  the  celebrated  German  chemist, 
Scheele,  made  a  more  scientific  examination  of 
the  action  of  light  on  the  silver  compounds, 
and  discovered  that  the  chloride  of  silver  black- 


8 


ens  more  rapidly  in  the  violet,  than  in  the  red 
ray  of  the  spectrum. 

The  first  attempt  at  photographing  was 
made  by  Wedgewood,  in  1802.  He  succeeded 
in  making  silhouettes  by  projecting  the  shadow 
of  the  object  on  paper  dipped  into  a  solution  of 
nitrate  of  silver ;  the  part  on  which  the  shadow 
fell  remained  white,  while  the  one  exposed 
to  the  light  blackened.  The  image  thus  ob- 
tained was  immersed  in  water,  which  dissolved 
the  unreduced  nitrate  of  silver.  Wedgewood 
and  Humphrey  Davy  tried  to  copy  landscapes 
in  the  camera  obscura  by  the  same  process,  but 
did  not  find  it  sensitive  enough.  Davy,  how- 
ever, succeeded  in  copying  the  enlarged  images 
obtained  with  the  solar  microscope. 

Joseph  Nicephore  Niepce  of  Chalons,  France, 
is  the  first  one  who  succeeded  in  fixing  the  im- 
age of  the  camera  obscura.  His  process  was 
based  on  the  property  of  the  bitumen  of  Judea, 
or  asphaltum,  to  become  insoluble  in  certain 
essential  oils  under  the  influence  of  ,  light. 
Niepce  dissolved  the  asphaltum  in  lavender 
essence,  and  spread  it  on  the  surface  of  a  sil- 
vered copper  plate  ;  when  dried,  the  plate  was 
exposed  in  the  camera  obscura  for  several 
hours,  and  then  washed  with  a  mixture  of  petrol 
oil  and  lavender  essence,  which  had  the  effect 
of  dissolving  the  unalted  asphaltum.  In  the 
image  thus  obtained,  the  lights  were  formed  by 
the  undissolved  bitumen,  and  the  shades  by 
the  silver. 


9 


In  1829  Niepce  associated  with  Daguerre, 
who  had  labored  to  attain  the  same  object,  but 
their  combined  efforts  did  not  result  in  improv- 
ing the  bitumen  process  so  as  to  make  it  prac- 
ticable. 

In  one  of  their  experiments,  they  used  the  va- 
por of  iodine  to  darken  the  shades  of  their 
bitumen  pictures,  and  observed  that  the  iodide 
of  silver  thus  formed  was  altered  in  color  by  the 
light.  It  is  this  fact,  which  is  said  to  have 
changed  the  direction  of  Daguerre's  investiga- 
tions, and  to  have  been  the  first  step  towards 
the  discovery  of  the  Daguerreotype. 

It  was  only  after  the  death  of  Niepce,  that 
Daguerre,  continuing  hik  experiments,  discov- 
ered the  process  which  bears  his  name.  Da- 
guerre's sensitive  iodide  of  silver  was  prepar- 
ed by  exposing  a  well  polished  silver  plate  to 
the  vapor  of  iodine.  The  plate  was  exposed 
in  the  camera  obscura  for  a  relatively  short 
time,  and  then  was  submitted  to  the  vapor  of 
mercury,  which  brought  out  the  latent  image. 
The  mercury  combining  with  the  parts  affect- 
ed by  the  light,  formed  the  lights,  while  the 
black  appearance  of  the  burnished  silver,  which 
had  not  been  impressed,  constituted  the  shades. 
The  unaltered  iodide  of  silver  was  then  ren- 
dered insensitive  by  washing  the  plate  with 
a  solution  of  common  salt. 

The  publication  of  Daguerre's  process  in 
1839,  produced  an  immense  sensation.  At  no 
time  and  on  no  occasion  before  was  a  greater 


10 


interest  manifested  by  the  lovers  of  art  and 
science.  Men  of  science  and  artists  of  reputa- 
tion embraced  the  new  art  with  enthusiasm, 
and  in  a  short  time,  the  Daguerreotype  became 
the  beautiful  process  as  it  is  now  practiced. — 
Daguerre  himself  did  but  little  to  perfect  it. — 
Baron  Seguier,  Foueault,  etc.,  perfected  the 
apparatus.  Herschel  substituted  hyposul- 
phite of  soda  for  the  common  salt  used  for 
fixing  the  image.  Fizeau  discovered  the 
means  of  gilding  the  image  and  in  this 
way  gave  it  more  brilliancy  and  durability. — 
Claudet  discovered  the  first  accelerating  sub- 
stance used,  the  chloride  of  iodine,  and  Fizeau 
again  used  the  vapor  of  bromine  to  the  same 
purpose,  and  thus  reduced  the  time  of  exposure 
in  the  camera  to  a  few  seconds.  After  that 
followed  the  discovery  of  the  dry  accelerating 
substances,  bromide  of  lime  and  chloro-bro- 
mide  of  lime  (improperly  called),  the  numerous 
improvements  in  the  apparatus,  by  which  the 
tedious  process  as  described  by  Daguerre  was 
reduced  to  its  utmost  simplicity,  etc. 

Thus,  in  a  few  years,  the  process  of  Photo- 
graphy on  silver  plates  became  the  simple  and 
practical  process  which  to  this  day  has  not  had 
its  superior  in  sharpness,  definition  and  brilli- 
ancy. 

While  Daguerre  was  prosecuting  his  re- 
searches in  France,  Fox  Talbot  was  continu- 
ing in  England  the  researches  of  Wedgwood 
and  Davy.  In  January 1839,  seven  months  be- 


11 


fore  the  publication  of  Daguerre's  process,  Mr. 
Talbot  made  his  first  communication  to  the 
Royal  Society  of  London.  In  this  communi- 
cation, he  made  known  his  process  of  copying 
by  application.  A  sheet  of  paper  is  firstly 
brushed  over  with  a  solution  of  chloride  of  so- 
dium (common  salt)  and  then  with  a  solution 
of  nitrate  of  silver.  In  this  way  is  formed  in 
the  texture  of  the  paper  a  white  precipitate  of 
chloride  of  silver,  a  compound  much  more  sen- 
sitive than  the  nitrate  of  silver  employed  by 
Wedgwood  and  Davy.  The  object  to  be  copied 
is  laid  on  the  prepared  paper  and  exposed  to 
the  light.  The  light  passes  through  the  trans- 
parent parts,  and  blackens  the  paper,  leaving 
unaltered  the  parts  through  which  it  cannot 
penetrate.  In  this  way  an  image  is  obtained 
with  the  lights  and  shades  reversed,  which 
Talbot  called  a  Negative.  This  negative  be- 
ing laid  on  a  .second  sheet  of  paper,  prepared 
in  the  same  way  as  the  first,  and  the  same 
operation  being  gone  through,  a  natural  repre- 
sentation of  the  object  is  obtained,  which  is 
called  Positive. 

In  February  1841,  Talbot  took  his  patent 
for  the  Talbotype  or  Calotype  process.  In  this 
process,  the  paper  is  first  brushed  over  with 
nitrate  of  silver,  then  with  iodide  of  potassium 
and  finally  with  gallo-nitrate  of  silver,  (a  solu- 
tion of  gallic  acid  and  nitrate  of  silver.)  It  is 
then  exposed  in  the  camera,  developed  with 
a  fresh  solution  of  gallo-nitrate,  and  fixed  in 


12 


a  solution  of  bromide  of  potassium.  The  im- 
age produced  is  negative,  and  positives  are 
copied  from  it  by  means  of  the  chloride  of  sil- 
ver paper  spoken  of  above.  The  Talbotype 
process  was  modified  and  perfected  by  Blan- 
quart  Evrard,  Humbert  de  Molar  d,  Baldus, 
Legray,  etc.  It  is  a  modification  of  the  Talbo- 
type process,  which  is  now  generally  used 
in  printing  enlarged  pictures. 

We  will  not  in  this  work  enter  into  the 
many  details  of  the  Calotype  process.  The 
different  negative  paper  processes  are  more 
suited  to  monumental  photography  than  to  the 
reproduction  of  natural  scenery.  Our  modern 
public  edifices,  the  elegant  and  tasteful  dwell- 
ings of  our  wealthy  citizens,  the  luxuriant  veg- 
etation of  our  landscapes  are  bad  subjects  to  be 
photographed.  Their  reproduction  presents  dif- 
ficulties which  can  only  be  overcome  by  means 
of  the  collodion  process.  The  processes  of  Le- 
gray, Baldus  and  others,  present  thus  too  little 
interest  to  our  American  photographers  to  speak 
at  length  of  them  in  this  work. 

Fox  Talbot  must  be  considered  as  the  inven- 
tor of  what  is  commonly  called  photography, 
which  comprises  the  different  processes  on  pa- 
per and  on  glass.  The  waxed  paper,  the  albu- 
men and  the  collodion  processes  rest  on  the 
same  basis  as  the  process  he  patented  in  Febru- 
ary, 1841,  viz:  formation  in  paper,  albumen  or 
collodion  of  iodide  of  silver  with  presence  of 
nitrate  of  silver,  moleculary  alteration  or  partial 


13 


reduction  of  the  sensitive  surface  by  the  light, 
development  or  bringing  out  of  the  latent  im- 
age by  means  of  gallic  acid,  pyrogallic  acid  or 
protosulphate  of  iron,  finally  desensitizing  or 
dissolution  of  the  unaltered  iodide  by  means 
of  bromide  of  potassium,  hyposulphite  of  soda, 
cyanide  of  potassium,  etc. 

The  prints  made  from  paper  negatives,  ow- 
ing to  the  coarse  and  irregular  texture  of  the 
paper,  being  very  inferior  in  sharpness  and 
definition  to  the  daguerreotypes,  Sir  John 
Herschel  suggested  the  use  of  glass  plates.— 
Soon  after  Mepce  de  St.  Victor,  the  nephew 
of  John  Mcephore  Mepce  discovered  the  Al- 
bumen process,  in  which  the  iodide  of  silver 
is  retained  on  the  plate  by  means  of  a  layer  of 
white  of  egg.  This  beautiful  process,  most 
simple  in  theory,  but  the  most  difficult  in  prac- 
tice was  perfected  by  Messrs.  Bayard,  Hum- 
bert de  Molard,  Martens,  Lemoynne,  Whipple, 
etc.  The  objections  to  this  process  are  the 
difficulty  to  avoid  dust  and  the  length  of  ex- 
posure that  is  required. 

In  1850  Legray  suggested  the  use  of  collo- 
dion instead  of  albumen,  but  Archer  was  the 
first  who  carried  out  the  idea  so  as  to  present 
to  the  photographic  world  a  well  defined  pro- 
cess. 

The  discovery  of  the  collodion  process  is 
the  most  important  that  has  been  made  in 
photography  since  the  discovery  of  the  Da- 
guerreotype.   It  has  given  an  immense  im- 


14 


pulse  to  the  art.  It  is  certainly  the  simplest 
and  most  successful  process  in  use,  and  is 
suited  to  almost  any  condition  of  light  and 
temperature. 

%  From  the  time  the  collodion  process  first 
came  into  use  attempts  have  been  made  to 
preserve  the  sensitiveness  of  the  film,  so  as  to 
be  able  to  leave  a  certain  time  between  the 
preparation  of  the  plate  and  the  exposure,  and 
between  the  exposure  and  the  development. 
Mr.  Shadbolt  first  succeeded  in  this  by  cover- 
ing the  sensitized  plate  with  diluted  honey, 
thus  keeping  it  moist.  This  process  is  now 
abandoned,  and  processes  in  which  the  plate  is 
washed  and  dried  have  come  into  general  use. 
Amongst  these  we  will  cite  Taupenot's  collodio- 
albumen  process,  Hill  Norris'  gelatine  pro- 
cess, Fothergill's,  Sutton's,  Major  Russell's 
and  others.  Major  Russell's  process,  in  which 
tannin  is  used  as  a  preservative,  is  the  most 
popular,  and  very  successful.  By  some  modi- 
fications introduced  in  its  practice,  good  results 
have  been  obtained  with  an  exposure  not  much 
longer  than  that  which  is  generally  given  for 
wet  collodion. 

The  attention  of  scientific  photographers  has 
been  directed,  for  the  last  few  years,  to  the 
means  of  preventing  the  fading  of  photographic 
prints.  The  researches  of  Messrs.  Barreswil 
and  Davanne,  Hardwich  and  others,  have 
shown  the  real  causes  of  the  fading. , 

Now  that  the  old  processes  of  toning  and  fix- 


15 

ing  together  have  been  abandoned,  and  the 
separate  toning  and  fixing  has  been  generally 
adopted,  prints  are  made  more  permanent  than 
they  used  to  be.  Many  photographers,  how- 
ever, use  their  fixing  bath  so  injudiciously 
that  the  prints  they  produce  are  little  better 
than  those  by  the  old  method. 

Some  experimenters  have  discovered  pro- 
cesses in  which  the  salts  of  silver  are  not  used. 
The  most  noted  one  is  the  carbon  process,  but 
the  prints  obtained  by  it  cannot  compete  for 
beauty  with  those  obtained  by  the  ordinary 
processes.  In  our  opinion  the  true  progress  of 
photography  lays  in  another  direction.  We 
refer  to  the  production  of  the  print  in  printer's 
ink.  The  process  of  photo-zincography  used 
at  the  ordnance  survey  office  in  Southampton, 
and  which  is  the  invention  of  Col.  H.  James 
and  Capt.  A.  De  C.  Scott,  gives,  in  the  hands 
of  these  gentlemen,  very  promising  results. 
The  same  may  be  said  of  Mr.  Osborne's  photo- 
lithographic process,  which  is  used  in  the  sur- 
vey office  in  Melbourne,  (Australia.)  Both 
processes  are  nearly  the  same,  and  are  subject 
to  the  same  objection,  the  difficulty  in  obtain- 
ing half  tone. 


16 


CHAPTER  II. 

Philosophy  of  Light — Decomposition  of  Light — Its 
Illuminating,  Heat  Producing  and  Actinic  Proper- 
ties— Invisible  Eays —  Refraction — Lenses  — The 
Photographic  Camera. 

When  a  pencil  of  sunlight  is  made  to  fall 
upon  one  angle  of  a,  prism,  it  is  decomposed  and 
forms  on  a  screen  placed  at  a  distance  an  image 
of  the  seven  primitive  colors  in  the  following 
order:  Violet,  Indigo,  Blue,  Green,  Yellow, 
Orange  and  Red.  This  image  is  called  the 
Solar  Spectrum.  This  experiment  which  was 
first  made  by  Newton,  proves  that  the  light 
of  the  sun  is  composed  of  seven  different  rays 
each  producing  a  different  illumination.  Some 
Philosophers  admit  only  of  three  primitive 
colors,  blue,  yellow  and  red,  and  contend  that 
the  violet,  indigo,  green  and  orange  are  form- 
ed by  two  or  more  of  these  overlapping  each 
other,  red  and  yellow  forming  orange,  yellow 
and  blue  forming  green,  etc. 

When  white  light  falls  on  opaque  bodies, 
some  of  the  rays  are  absorbed,  others  are  re- 
flected. A  red  surface  thus  reflects  the  red 
ray  and  absorbs  the  others,  a  blue  surface  re- 
flects the  blue  ray,  white  surfaces  reflect  the 
light  without  decomposing  it,  while  black 
ones  absorb  all  the  rays. 

The  same  phenomenon  takes  place  when 
white  light  is  transmitted  through  transparent 
or  translucid  bodies.    While  white  glass  will 


17 


thus  transmit  the  light  without  decomposition, 
orange  glass  will  only  transmit  the  orange 
ray,  blue  glass  only  the  blue  ray. 

The  compound  light  produces  three  effects : 
it  illuminates,  it  produces  heat,  and  it  has  a 
*   chemical  power  commonly  called  actinism. 

The  power  of  illuminating  resides  mainly 
in  the  yellow  ray,  the  part  of  the  spectrum 
occupied  by  that  ray  being  the  brightest.  The 
heating  properties  are  predominant  in  the  red 
ray ;  a  thermometer  held  in  that  part  of  the 
spectrum  indicates  an  increase  of  temperature. 

The  most  intense  actinic  power  is  to  be 
found  in  the  blue,  indigo  and  violet  rays.  Thus, 
when  a  sheet  of  sensitized  paper  is  exposed 
to  the  decomposed  light  in  the  spectrum,  the 
action  will  be  found  to  be  the  most  energetic  in 
the  space  occupied  by  these  rays.  But  this 
action  is  not  confined  within  the  limits  of  the 
spectrum,  for  the  paper  will  be  impressed  also 
beyond  the  violet  where  the  eye  perceives  no 
light.  The  actinic  rays  which  produce  this 
&re  called  invisible,  or  dark  rays. 

When  the  light  passes  from  one  medium 
into  another,  one  part  of  it  is  reflected,  the 
other  part  entering  the  new  medium  is  bended, 
Bef  Taction  is  the  property  which  light  possess- 
es of  deviating  from  its  primitive  direction,  on 
passing  from  a  medium  of  a  certain  density 
into  another  of  different  density.  The  effects 
of  refraction  are  illustrated  by  some  very  sim- 
ple experiments.    If  a  stick  be  put  into  the  wa- 

2 


18 

ter  it  will  seem  to  be  broken  in  two.  If  a 
coin  be  dropped  into  a  tub  of  water,  it  will  ap- 
pear much  nearer  the  observer  than  it  really 
is.  By  the  effect  of  refraction,  a  fish  will  ap- 
pear nearer  the  surface,  a  basin  or  a  river  will 
not  appear  as  deep  as  it  really  is.  We 
see  the  stars  at  their  rising,  before  the  mo- 
ment the  rays  emanating  from  them  can 
arrive  in  a  straight  line  within  the  reach  of 
our  vision,  because  these  rays  are  refracted 
by  entering  the  atmosphere  which  surrounds 
the  globe. 

When  a  ray  of  light  falls  upon  a  lens,  the 
phenomenon  of  refraction  takes  place.  The 
ray  bends  on  entering  the  lens  and  bends 
again  on  leaving  it.  The  form  of  the  lens  de- 
termines the  direction  of  the  refracted  rays. 

Convergent  lenses  are  those  which  refract 
the  rays  so  as  to  condense  them  to  a  point, 
divergent  lenses  are  those  which  scatter  them. 

A  biconvex  lens  is  one  which  is  convex  on 
both  sides.  A  biconcave  lens  is  concave  on 
both  sides.  A  meniscus  lens  is  convex  on  one 
side  and  concave  on  the  other,  but  more  con- 
vex than  concave.  A  plano-convex  lens  is 
plane  on  one  side  and  convex  on  the  other. — 
The  bi-convex,  meniscus  and  plano-convex  len- 
ses condense  the  light  to  a  point  and  are  thus 
convergent,  the  bi-concave  and  plano-con- 
cave lenses  scatter  it  and  are  therefore  diver- 
gent. 

The  point  at  which  rays  of  light  are  brought 


19 


together  by  convergent  lenses  is  called  the 
focus. 

When  rays  of  light  proceed  from  very  distant 
objects,  they  are  parallel,  or  may  be  considered 
so.  Parallel  rays,  entering  a  convergent  lens, 
are  brought  to  a  focus  at  a  point  nearer  the 
lens  than  rays  which  proceed  from  a  small  dis- 
tance and  are  divergent.  The  nearer  the  ob- 
ject from  which  the  rays  proceed  the  farther  the 
focus  is  from  the  lens.  The  sun's  rays  which 
are  parallel,  condense  to  a  point  which  is  called 
the  principal  focus.  It  is  to  this  point  that 
reference  is  made  in  speaking  of  the  focal 
length  of  a  lens. 

When  a  ray  of  light  proceeds  from  a  near 
point,  and  passing  through  a  lens,  comes  to  a 
focus  at  another  point,  these  two  points  asso- 
ciated are  termed  conjugate  foci. 

The  nearer  the  object  is  to  the  lens,  the  far- 
ther its  focus  will  be  removed  from  it,  and 
the  larger  the  image  will  be. 

The  more  convex  the  lens  is,  the  shorter  the 
focus,  and  the  smaller  the  image  it  gives. 

The  Photographic  Camera,  in  its  most  simple 
form,  is  a  box  composed  of  two  compartments, 
the  one  sliding  into  the  other,  one  compart- 
ment having  a  lens  adapted  to  it,  the  other 
being  furnished  with  a  ground  glass,  which  can 
be  removed  and  a  tablet  holding  the  sensitive 
plate  put  in  its  place.  When  this  camera  is 
pointed  towards  an  object  the  focus  is  found 
by  sliding  the   compartment  to  which  the 


20 


ground  glass  is  adapted,  forwards  and  back 
wards,  till  the  point  is  found  where  the  image 
is  the  most  distinct. 

The  image  formed  on  the  ground  glass  is 
more  or  less  flat  or  curved,  sharp  or  indistinct. 
This  depends  on  the  construction  of  the  lenses 
or  object-glasses.  An  object-glass,  which  gives 
an  image  of  which  nearly  all  the  parts  can  be 
brought  to  a  focus  at  the  same  point,  is  said  to 
have  a  flat  field.  Object-glasses  giving  very 
sharp  images,  have  generally  a  curved  field, 
so  that  when  the  center  of  the  image  is  in 
focus,  the  extremities  are  not.  Flat  fields,  on 
the  other  side,  are  obtained  at  the  expense  of 
sharpness. 

The  want  of  definition  of  one  part  of  the 
image,  when  the  other  is  sharp  and  distinct, 
is  due  to  two  causes.  The  first  one  is  the  un- 
equal refraction  of  the  rays  of  light,  resulting 
from  the  spherical  form  of  the  lenses,  and  is 
called  spherical  aberration.  The  second  cause, 
is  the  obliquity  of  some  rays  proceeding  from 
the  object.  This  indistinctness  of  the  edges 
of  the  image,  can  be  corrected  by  covering  the 
edges  of  the  lens,  in  which  the  spherical  aber- 
ration mainly  resides,  and  admitting  the  light 
only  through  the  center.  This  is  done  by  fix- 
ing in  front  of  the  lens  a  disc  of  metal  or  card- 
board with  a  circular  or  square  opening  in  the 
center.  This  disc  is  called  stop  or  diaphragm. 
The  effect  of  a  stop  is  also  to  make  the  field 
flatter,  by  intercepting  a  portion  of  the  oblique 


21 


rays,  and  thus  lengthening  out  the  focus  of  the 
remainder.  These  effects  are  produced  to  a 
greater  extent  in  proportion  as  the  diaphragm 
is  smaller.  But  in  the  same  time,  the  quan- 
tity of  light  admitted  into  the  camera,  being 
diminished,  the  image  is  less  illuminated,  and 
the  sensitive  plate  requires  a  longer  exposure. 

In  such  conditions,  when  the  use  of  dia- 
phragms is  not  practicable,  it  is  necessary  to 
use  lenses,  with  the  least  possible  spherical 
aberration.  The  manufacture  of  such  lenses  is 
a  work  of  great  skill  and  difficulty,  and  re- 
quires extraordinary  care. 

Ordinary  lenses  refracting  the  light,  decom- 
pose it,  and  give  images  fringed  with  color. 
This  effect  is  called  chromatic  aberration,  and  is 
corrected  by  the  combination  of  two  lenses  of 
different  density ;  a  bi-concave  flint,  and  a  bi- 
convex crown,  sealed  together,  so  that  they 
form  a  meniscus,  which  is  called  achromatic. 

The  achromatic  meniscus,  in  order  to  give 
the  desired  sharpness  and  field,  requires  to  be 
diaphragmed,  but  as  the  diaphragm  shuts  off 
a  large  part  of  the  light,  it  makes  it  impossible 
to  use  this  combination  to  reproduce  images 
of  objects  which  require  rapidity  of  action. 

The  portrait  tube,  or  object-glass,  is  a  double 
combination  of  lenses.  The  front  combination 
is  a  bi-convex  crown,  sealed  to  a  plano-concave 
flint,  and  has  the  crown  lens  turned  towards 
the  object;  the  back  combination  is  composed 
of  a  bi-concave  flint,  slightly  separated  from  a 


22 


bi-convex  crown  by  means  of  a  ring,  the  crown 
lens  facing  the  ground  glass.  The  distance 
between  the  two  compound  lenses  is  deter- 
mined by  calculation. 

The  portrait  combination  is  generally  used 
without  a  diaphragm,  so  as  to  allow  a  short 
exposure  of  the  sensitive  plate,  by  admitting 
a  large  volume  of  light. 

The  most  essential  conditions  required  in  a 
portrait  tube,  are :  rapidity  of  action,  sharpness, 
and  depth  of  focus.  The  most  important  one 
is  the  lust,  as  without  it,  the  production  of 
good  portraits  is  impossible,  those  parts  only 
on  which  the  focus  has  been  taken  coming  out 
sharp  and  distinct,  and  the  other  being  dis- 
torted and  out  of  focus.  It  is  for  want  of  depth 
of  focus,  that  in  so  many  portraits  the  hands, 
and  other  parts,  are  out  of  shape,  and  a  great 
deal  larger  than  they  are  in  nature.  This  de- 
fect can  be  obviated,  to  a  certain  extent,  by 
setting  the  subject  so  that  his  body  describes 
a  segment  of  a  circle,  as  far  as  this  is  compe- 
tent with  a  good  and  easy  position.  Operators 
possessing  instruments  which  have  this  defect 
should  diaphragm  them  as  much  as  their 
light  and  the  sensitiveness  of  their  plates 
will  allow,  and  they  should  not  attempt  to 
make  large  heads,  if  they  want  to  have  good 
likenesses. 

The  portrait  combination  can  be  used  also 
for  views,  by  inserting  a  small  diaphragm 
between  the  lenses ;  or  the  back  lenses  may  be 


23 


removed,  and  the  front  lens*  turned  with  the 
plane  side  towards  the  object,  in  which  case,  a 
diaphragm  has  to  be  adapted  in  front. 

The  refraction  of  the  light  through  a  lens, 
which  produces  chromatic  aberration,  separates 
also  the  visual  from  the  chemical  focus.  We 
have  seen  that  the  most  intense  actinic  effect 
resides  in  the  violet  ray,  and  beyond  it,  and 
that  the  most  luminous  portion  of  the  spectrum 
is  the  space  occupied  by  the  yellow  ray.  The 
violet  ray  being  more  refrangible  than  the  yel- 
low ray,  will  be  more  strongly  bent,  and  the 
two  rays  will  be  brought  to  a  focus  at  two  dif- 
ferent points.  The  most  intense  chemical 
action  will  thus  not  take  place  at  the  point 
where  the  image  is  the  sharpest,  but  at  a  point 
nearer  the  lens ;  and  whenever  lenses  are  used, 
which  are  not  strictly  achromatic,  the  slide 
containing  the  sensitive  plate  should  be  shifted 
to  that  point.  In  the  lenses  made  by  good 
manufacturers,  however,  the  visual  and  chem- 
ical focus  are  made  to  correspond. 


CHAPTER  III. 

General  Theory  of  the  Collodion  Process. 

Collodion  is  a  solution  of  Pyroxyline  or  Grun- 
cotton  in  a  mixture  of  Sulphuric  Ether  and 
Alcohol. 


24 


Iodized  collodion,  is  collodion  in  which  a 
certain  quantity  of  some  Iodkle  has  been  dis- 
solved, the  iodide  of  potassium,  for  instance. 

If  a  glass  plate  be  coated  with  this  iodized 
collodion,  and,  after  part  of  the  ether  and  al- 
cohol are  evaporated,  be  immersed  into  a  so- 
lution of  nitrate  of  silver,  the  iodide  of  potas- 
sium and  nitrate  of  silver  will  decompose  each 
other  and  will  produce  iodide  of  silver,  which 
will  be  retained  on  the  plate  by  the  film  of 
the  collodion.  In  this  state,  the  film  will  pre- 
sent a  blue,  white,  or  creamy  opaque  appear- 
ance according  to  the  quantity  of  iodide  of  po- 
tassium dissolved  in  the  collodion.  This  ope- 
ration has  to  be  done  in  a  dark  room  by  arti- 
ficial light.  If  we  now  expose  this  plate  in  the 
camera,  the  film  will  be  impressed  by  the  rays 
of  light,  strongly  in  the  clear  parts,  to  a  small- 
er extent  in  the  darker.  In  examining  the 
plate  at  this  moment,  it  will  be  found  to  have 
the  same  appearance  as  before,  presenting  no 
trace  of  an  image.  A  latent  image  exists 
however,  which  has  to  be  brought  out  by  means 
of  a  developer.  The  developer,  in  the  collodi- 
on process  is  either  protosulphate  of  iron 
or  pyrogallic  acid.  If  then,  we  pour  a  solu- 
tion of  protosulphate  of  iron  on  the  plate,  the 
image  will  appear,  presenting  the  most  inten- 
sity in  those  places  where  the  light  was  the 
strongest.  This  image  is  formed  by  metallic 
silver  in  a  minute  state  of  division  retained  on 
the  plate  by  the  film  of  collodion.    At  this 


25 


period  we  have  on  the  plate  metallic  silver 
and  iodide  of  silver  which  have  not  been  acted 
upon.  What  remains  to  be  done  is  to  take 
away  this  Iodide  of  silver  by  dissolving  it  in 
cyanide  of  potassium  or  in  hyposulphite  of 
soda. 

Let  us  now  examine  the  picture  which  we 
have  obtained,  by  holding  it  up  to  the  light. 

We  will  observe  that  the  light  parts  present 
a  certain  opacity  and  that  the  shadows  are 
transparent.  If  on  the  contrary,  we  examine  it 
by  reflection  we  will  find  that  the  light  parts 
appear  white  and  the  shadows  black.  The 
former  appearance  of  the  picture  is  called  the 
Negative,  and  the  latter  the  Positive. 

All  collodion  pictures  made  on  transparent 
surfaces  such  *as  glass,  etc  present  both  as- 
pects: Those  made  on  ppi tuned  iron  plates  or 
on  black  paper,  can  aiy  be  viewed  as  posi- 
tives. In  practice,  the  name  of  positives  is 
given  to  such  pictures  on  glass,  iron,  paper,  etc, 
that  are  designed  to  be  viewed  by  reflected 
light.  On  the  contrary,  negatives  are  judged 
of  by  transmitted  light  and  are  a  kind  of  type  or 
matrix,  with  which  pictures  on  paper  have  to 
be  produced  by  means  of  a  peculiar  printing 
process. 

Although  a  collodion  glass  picture  presents 
both  aspects,  the  positive  and  the  negative,  it 
cannot  be  used  in  both  qualities.  A  good 
positive  picture  has  never  opacity  enough  in 
the  light  parts  to  be  used  for  making  prints; 

3 


26 


and  a  negative  picture,  viewed  by  reflection  is 
imperfect,  owing  to  the  absence  of  good  blacks 
and  of  details  in  the  light  parts.  Both  kinds 
jof  pictures  are  produced  by  the  same  process, 
but  different  conditions  of  the  chemicals  are 
required. 

For  the  positive  picture,  the  silver  reduced 
on  the  surface  of  the  plate  has  to  be  in  a  small 
quantity  only;  for  the  negative  picture,  it  is  to 
be  so  thick  that  it  obstructs  the  light  to  a  con- 
siderable extent  in  the  light  parts.  The 
quantity  of  reduced  silver,  or  the  intensity  of 
the  image,  depends ;  1st,  on  the  peculiar  qual- 
ities of  the  soluble  cotton;  2nd,  on  the  thick- 
ness of  the  collodion;  3d,  on  the  amount  of 
bromide  dissolved  in  the  collodion ;  4th,  on  the 
condition  of  the  silver  solution  and  of  the 
developing  solution ;  5th,  on  the  length  of  ex- 
posure in  the  camera. 


CHAPTER  IV. 

On  the  different  Compounds  used  in  the  Production 
of  Collodion  Pictures. 

Before  we  enter  upon  the  practical  details 
for  the  production  of  collodion  pictures,  we 
will  give,  first,  the  preparation  of  the  different 
solutions  to  be  used.  These  are  taken  in  the 
following  order:  1st,  the  collodion ,  2nd,  the 
silver  solution ;  3d,  the  developing  solution ; 
4th,  the  fixing  solution. 


27 


The  collodion  is  the  menstruum  used  to  re- 
tain the  sensitive  compound  on  the  glass,  or 
on  the  iron  plate ;  the  silver  solution,  in  com- 
bination with  the  iodine,  which  is  in  the  col- 
lodion, forms  the  sensitive  compound ;  the  de- 
veloping solution  brings  the  latent  image  out ; 
and  the  fixing  solution  removes  from  the  film 
the  unreduced  sensitive  compound. 


CHAPTER  V. 

On  Positive  Collodion  Pictures. 

A  positive  collodion  picture  is  understood  to 
be  a  collodion  picture  viewed  by  reflected  light. 
Positive  pictures  are  made  on  different  mate- 
rials. Those  most  commonly  used  are  whi^e 
or  colored  glass,  japanned  iron  plates,  or  card- 
board prepared  in  a  similar  way,  mica,  etc. 
Positives  made  on  glass  are  generally  called 
Ambrotypes,  a  name  originally  only  applied  to 
such  pictures  as  were  sealed  to  another  plate 
of  glass  by  means  of  balsam  of  fir,  and  in  this 
way  were  kept  from  deteriorating  influences. 
Pictures  made  on  iron  plates  are  called  Me- 
lainotypes  or  Ferrotypes;  and  those  made  on 
card  board  or  paper  covered  with  asphaltum 
varnish,  are  known  by  the  name  of  Mellographs.  * 
The  use  of  black  paper  and  mica  is  now  almost 
entirely  abandoned,  professional  photographers 
confining  themselves  to  the  glass  and  iron 
plates. 


28 


The  pictures  on  iron  plates  and  on  black 
paper  are  like  the  daguerreotype  reversed, 
that  is,  the  image  is  the  same  as  seen  in  a 
looking  glass,  the  right  side  being  left,  and  the 
left  right.  The  ambrotype  alone  can  be 
mounted  so  as  to  give  an  exact  representation 
of  the  subject,  and  in  that  case  the  black  var- 
nish, velvet  or  paper  have  to  be  applied  on  the 
collodion  side,  and  the  color  that  may  be  put 
on  the  picture,  will  not  show  through  the  film. 
The  fact  of  the*  melainotype  and  niellograph 
being  reversed  is  not  objectionable  in  most 
cases  in  portraits,  but  is  decidedly  so  in  views 
and  in  this  case  a  parallel  reflector,  or  a  prism 
will  have  to  be  used  to  invert  the  image,  or 
the  picture  will  have  to  be  made  on  glass. 

*In  our  opinion  the  melainotype,  covered  with 
benzine  varnish,  is  the  most  durable  picture 
of  all,  as  much  because  of  the  durability  of  the 
material  on  which  it  is  made,  as  from  the 
great  adherance  of  the  collodion  film  and  var- 
nish to  the  japanned  surface.  We  never 
knew  a  melainotype  picture  to  crack  off, 
while  this  is  quite  common  with  the  varnished 
glass  pictures,  which  are  exposed  in  show 
cases  to  the  inclemency  of  the  weather.  The 
iron  plate  is  further  incomparably  easier 
to  manage  than  glass ;  it  can  be  grasped  by 
the  pinchers,  cut,  heated  for  drying  and  var- 
nished with  ease  and  safety,  and  the  subsequent 
varnishing  on  the  back,  in  mounting  positives 
on  glass,  after  the  impression  is  obtained,  is 


29 


avoided  by  its  use.  Another  advantage  is, 
the  facility  with  which  the  plates  are  cleaned, 
a  piece  of  canton  flannel,  and  a  few  drops  of 
alcohol,  are  all  that  is  required  for  the  pur- 
pose. 

What  has  been  said  of  the  melainotype 
plate,  is  applicable  in  a  great  measure  to  the 
niello  paper.  However,  the  material  of  which 
it  is  made  is  not  as  durable,  and  the  paper 
plates  present  the  inconvenience  of  floating  in 
the  silver  solution,  so  that  they  have  first  to 
be  stuck  on  a  glass  before  they  are  immersed 
in  it. 

Sometimes  pictures  are  first  made  on  glass, 
and  then  transferred  on  oil-cloth,  or  on  patent 
leather.  They  are  not  reversed,  and  require 
no  varnishing,  the  metallic  silver  forming  the 
picture  being  protected  by  the  part  of  the  col- 
lodion film  which  adheres  to  the  glass.  These 
cannot  be  colored. 


CHAPTER  VI.  * 

On  Collodion. 

Three  compounds  enter  into  the  preparation 
of  collodion;  ether,  alcohol,  and  pyroxyline 
or  soluble  gun-cotton. 

Ether, — (Commonly  but  improperly  called 
sulphuric  ether.)  The  purity  of  the  ether  is  a 
matter  of  great  importance,  in  the  preparation 
of  good  collodion.    It  must  be  concentrated, 


30 


free  from  much  alcohol  and  water,  without  dis- 
agreeable smell,  and  free  from  acetic  and 
sulphuric  acids. 

Three  kinds  of  ether  are  ordinarily  found  in 
the  trade. 

First,  the  common  ether,  which  contains  a 
variable  quantity  of  alcohol  and  water,  and 
presents  ordinarily  an  acid  reaction  with  lit- 
mus paper,  from  the  presence  of  sulphuric 
acid.    Ether  in  this  state  is  unfit  for  use. 

Second,  the  washed  ether,  or  ordinary  ether 
which  has  been  agitated  with  a  certain  quantity 
of  water,  to  take  away  the  alcohol  and  the 
acid.  This  might  be  used  in  connection  with 
very  strong  alcohol,  and  cotton  of  good  qual- 
ity, if  it  was  washed  so  thoroughly  as  to  pre- 
sent no  longer  an  acid  reaction  to  test  paper. 

Third,  ether  both  washed  and  redistilled,  on 
unslacked  lime  or  on  potash,  which  deprives 
it  of  its  water,  and  neutralizes  any  acid  it  may 
contain.  This  ether  is  the  best  for  use,  and 
should  always  be  procured  if  possible.  When 
entirely  pure,  its  specific  gravity  is  720,  but, 
it  is  but  seldom  found  at  that  strength.  The 
ether  expressly  prepared  for  photographic  pur- 
poses, by  reliable  chemists,  has  a  specific  grav- 
ity of  about  725.  The  minimum  of  strength 
of  the  ether  to  be  used  depends  entirely  on 
the  strength  and  quantity  of  alcohol  used  in 
connection  with  it,  to  dissolve  the  pyroxline. 

If  the  practitioner  cannot  find  any  ether 
strong  enough  for  use,  he  may  take  the  com- 


31 


mon  or  washed  ether  and  deprive  jt  of  its 
water  by  digesting  it  with  good  white  unslacked 
lime.  The  effect  of  the  quick  lime  is  to  absorb 
the  water  and  neutralize  the  acid.  The  ether 
should  be  put  in  a  bottle,  and  the  lime  added 
to  it  by  small  quantities  at  a  time,  and  at  in- 
tervals of  half  an  hour,  shaking  after  each  ad- 
dition. The  quantity  of  lime  to  be  used  is 
two  or  three  ounces  to  a  pound  of  ether.  Af- 
ter all  the  lime  has  been  added,  let  it  digest 
for  a  day  or  two,  shaking  occasionally,  after 
which  the  ether  will  be  deprived  of  its  water. 
The  clear  liquid  can  then  be  poured  off  and 
kept  for  use.  It  will  happen,  sometimes,  that 
the  lime  absorbs  the  water  very  quickly,  which 
produces  an  elevation  of  temperature.  If  so, 
groat  care  should  be  taken  not  to  add  too  much 
lime  at  a  time,  for  the  ether,  being  very  vola- 
tile, might  blow  off  the  cork  of  the  bottle. — 
The  ether,  concentrated  this  way,  is  slightly 
alkaline,  but  the  alkalinity  is  removed  easily, 
by  adding  hydrobromic  acid  to  the  collodion 
till  it  takes  a  yellow  straw  color  after  being 
kept  a  few  hours. 

Ether  which  is  exposed  to  the  light  and  to 
the  contact  of  the  air,  will  decompose  and  gen- 
erate acetic  acid.  In  this  state,  it  is  unfit  for 
photographic  purposes.  It  is  necessary  for  its 
preservation,  to  put  it  into  well  corked  bottles, 
and  to  keep  it  in  a  dark  place. 

Alcohol — It  is  necessary  to  use  the  purest 
alcohol,  not  weaker  than  90  per  cent,  when  it 


32 


is  used  with  ether  725,  and  stronger  when  it 
has  to  be  used  with  ether  of  a  greater  specific 
gravity.  It  should  also  be  free  from  essential 
oil.  Quick  lime  will  bring  common  alcohol  to 
a  standard  suitable  for  photographic  purposes, 
It  should  be  used  in  the  same  proportion,  and 
in  the  same  way,  as  for  the  concentration  of 
the  ether. 

Pyroxyline  or  soluble  gun  cotton.— Pyroxy- 
line  made  from  cotton  has  the  same  appearance 
and  physical  properties  as  ordinary  cotton, 
with  the  difference  that  it  is  somewhat  more 
rough  to  the  touch  and  that  it  grates  in  being 
pulled  apart  through  the  fingers. 

Pyroxyline  is  the  result  of  the  action  of  ni- 
tric acid  on  ligneous  substances,  such  as  cotton, 
paper,  linen,  wood,  etc. 

For  the  manner  of  its  preparation,  we  refer 
the  reader  to  the  4  Chemistry  of  Pyroxyline? — • 
We  will  only  say  here,  that  it  is  produced  by 
immersing  the  cotton  in  a  mixture  of  nitric 
and  sulphuric  acids. 

The  quality  of  the  soluble  cotton  depends, 
1st,  on  the  strength  of  the  acids.  2nd,  on  the 
temperature  of  the  acids  during  the  immersion. 

The  strength  of  the  acids  determines  the 
more  or  less  solubility  of  the  cotton.  Cotton 
immersed  into  a  mixture  of  nitric  and  sulphu- 
ric acids  of  the  maximum  of  strength  is  ex- 
plosive, but  insoluble  in  the  mixture  of  ether 
and  alcohol.  In  proportion  as  the  strength  of 
the  acids  is  reduced  by  the  addition  of  water, 


33 


the  cotton  becomes  less  explosive  and  more 
soluble,  till  it  reaches  a  certain  point,  when 
the  solubility  decreases.  Thus  both  strong 
and  weak  acids  give  insoluble  or  imperfectly 
soluble  cotton.  The  one  obtained  by  strong 
acids  is  more  or  less  explosive ;  the  one  ob- 
tained by  weak  acids  burns  without  explo- 
sion. 

The  temperature  of  the  acids  during  the 
immersion,  the  acids  supposed  to  be  of  the 
proper  strength,  determines  the  physical  pro- 
perties of  the  plain  collodion.  Pyroxyline 
made  at  the  maximum  of  temperature,  gives 
a  collodion  presenting  the  following  peculiari- 
ties ;  1st. — -When  added  to  the  ordinary  pro- 
portion of  ether  and  alcohol,  it  falls  to  the  bot- 
tom in .  a  gelatinous  mass,  and  dissolves  only 
after  considerable  shaking.  2nd. — It  yields  a 
fluid  solution,  and  requires  to  be  used  in  a 
comparatively  large  quantity  to  make  a  collo- 
dion of  the  proper  thickness.  3rd. — It  gives 
a  collodion  spreading  into  a  smooth  and  glassy 
surface.  4th. — The  film  it  gives  is  short,  ad- 
herant  to  the  glass,  and  porous. 

Pyroxyline  made  at  a  low  temperature,  pre- 
sents the  opposite  characteristics.  1st. — It 
dissolves  in  the  mixture  of  ether  and  alcohol 
without  gelatinizing.  2nd. — It  gives  a  thick 
and  glutinous  solution.  3rd. — It  gives  a  col- 
lodion spreading  over  the  glass  in  a  slimy 
manner,  and  setting  into  numerous  small 
waves.    4th. — The  film  is  tough,  contractile, 


34 


coherant,  apt  to  get  loose  from  the  glass  and 
devoid  of  porosity. 

When  acids  of  the  minimum  of  strength, 
and  at  a  high  temperature  act  on  cotton,  it  is 
liable  to  be  partly  decomposed  and  the  collo- 
dion made  with  it  will  be  porous  to  a  high  de- 
gree. Such  cotton  will  have  a  short  texture, 
and  sometimes,  give  a  rotten  film,  which  will 
crack  on  drying. 

Pyroxyline,  mainly  the  one  that  has  been 
made  at  a  high  temperature,  is  liable  to  be  de- 
composed. The  first  symptoms  of  this  decom- 
position, are  a  strong  acid  smell,  and  a  disin- 
tegration of  the  cotton,  the  fibers  becoming 
short  and  broken.  Then  follows  the  reduction 
to  a  fine  white  powder,  and  finally  to  a  glutin- 
ous mass,  which  on  the  addition  of  water  de- 
gages  abundant  vapors  of  peroxid  of  nitrogen. 
The  conditions  most  favorable  to  this  decom- 
position, seem  to  be  heat  and  compression. 
The  contact  of  the  air  seems  to  be  unfavorable 
to  it,  contrary  to  what  has  been  advanced,  for 
the  soluble  cotton  will  decompose  much  sooner 
in  closely  stoppered  bottles,  than  in  tin  or  paper 
boxes,  or  when  wrapped  up  in  paper.  It 
should  thus  be  packed  rather  loosely,  mainly 
in  the  summer  months,  or  in  warm  climates. 

Acidity  of  the  soluble  cotton,  resulting  either 
from  imperfect  washing,  or  a  commencement 
of  decomposition,  is  very  objectionable,  as  the 
acid  decomposes  the  iodides  and  bromides  used 
to  sensitize,  setting  iodine  free,  and  giving 


35 


a  red  color  to  the  collodion.  If  the  cotton 
has  an  acid  smell,  it  should  be  washed 
with  water,  until  all  the  acidity  has  been 
removed,  which  can  be  detected  by  means 
of  litmus  paper.  It  should  then  be  pressed 
out  in  a  towel,  and  allowed  to  dry.  If  you 
wish  it  to  dry  rapidly,  wash  the  remaining 
water  out  with  alcohol,  and  then  press  the 
alcohol  out.  - 

A  mixture  of  ether  and  alcohol  dissolves 
the  soluble  cotton,  but  neither  of  these  liquids 
will  dissolve  it,  when  employed  alone.  Sup- 
posing the  ether  to  be  of  a  specific  gravity, 
from  725  to  730,  the  alcohol  from  92  to  95  per 
cent,  and  the  cotton  of  good  quality,  the  fol- 
lowing formula  will  be  found  to  be  most  gen- 
erally admissible. 

Ether  ,  4  oz.  fluid. 

Alcohol  4  oz.  fluid.  • 

Cotton  from  30  to  60  grains. 

Put  the  cotton  into  the  bottle,  pour  on  the 
alcohol,  shake,  then  pour  on  the  ether,  and 
shake  again,  till  all  the  cotton  is  dissolved. 
Or,  the  ether  and  alcohol  can  be  first  mixed 
together,  and  then  the  cotton  added  to  it,  but 
in  this  way  it  takes  longer  to  effect  the  solu- 
tion. 

The  proportion  of  cotton  to  be  used  in  the 
collodion  is  variable,  one  cotton  giving,  when 
used  in  the  same  proportion,  a  great  deal 
thicker  collodion  than  another.  This,  as  we 
have  seen  already,  is  owing  to  the  temperature 


36 


of  the  nitro-sulphuric  acid,  the  cotton  made 
at  a  high  temperature  giving  a  more  fluid 
solution  than  the  one  made  at  a  lower.  The 
photographer  can  thus  only  judge  of  the  quan- 
tity of  cotton  he  has  to  use  by  coating  a  glass 
with  the  collodion  made  w^ith  it. 

Cotton,  possessing  to  an  extreme  degree  the 
peculiarities  resulting  from  having  been  made 
at  a  low  temperature,  is  not  suitable  for  pho- 
tographic purposes.  If  it  has  these  peculiar- 
ities only  in  a  small  degree,  the  plain  collodion 
made  with  it  can  be  corrected  in  three  different 
ways.  1st, — By  increasing  the  proportion  of 
alcohol,  using  for  this  purpose  alcohol  of  at 
least  95  per  cent.  2nd, — By  adding  chloro- 
form, in  the  proportion  of  one  or  two  drachms 
to  a  pound.  3rd, — By  decomposing  it  par- 
tially by  the  addition  of  aqua  ammonia.  The 
ammonia,  like  all  other  alkalies,  decomposes 
the  pyroxyline,  and  makes  the  solution  fluid, 
so  that  it  yields  a  beautiful,  even,  and  porous 
film.  The  same  effect  is  produced  in  iodized 
collodion,  by  the  alkaline  iodides  and  brom- 
ides, but  to  a  smaller  extent.  The  way  of  pro- 
ceeding is  to  add  five  or  six  drops  of  strong 
ammonia  to  about  a  pint  of  collodion,  testing 
it  every  clay,  and  when  it  has  come  to  the 
proper  condition,  neutralizing  the  remaining 
ammonia  with  hydrobromic  acid.  The  prac- 
titioner should  be  cautious  against  using  too 
much  ammonia,  or  letting  it  act  too  long  a 
time,  for  the  film  would  become  so  rotten  that 


37 


a  stream  of  water  would  wash  it  off  the 
glass,  or,  if  the  decomposition  was  not  quite 
carried  to  that  point,  it  would,  after  drying, 
be  cracked  all  over,  just  as  if  the  cotton  had 
been  partly  decomposed  in  the  acid,  or  as  if 
too  much  water  was  present  in  the  collodion. 
If,  however,  the  effect  of  the  ammonia  was 
carried  too  far,  the  remedy  would  be  to  mix 
the  rotten  collodion  with  some  newly  made, 
till  a  mixture  is  obtained  which  has  the  de- 
sired properties. 

Independently  of  the  quality  of  the  pyroxy- 
line,  the  resulting  solutions  differ  in  character, 
according  to  the  relative  proportions  of  the 
solvents  employed.  When  the  ether  is  used 
in  a  large  quantity,  the  collodion  film  spreads 
with  difficulty  over  the  plate,  owing  to  the 
rapid  evaporation.  The  film  is  very  tough, 
coherent  and  contractile,  so  that  it  will  often 
separate  from  the  sides  of  the  glass,  if  not 
handled  and  dried  with  precaution.  It  is 
also  devoid  of  porosity.  When,  to  such  a 
collodion,  alcohol  is  added  in  suitable  propor- 
tions, all  these  inconveniences  are  removed, 
and  it  will  spread  with  more  regularity,  and 
give  an  even,  soft,  and  easily  torn  film,  which 
possesses  great  adherence  to  the  plate,  and  has 
no  tendency  to  contract  or  peel  in  drying. 

We  see  thus  that  the  character  of  a  plain 
collodion,  with  an  excess  of  ether,  is  similar 
to  the  one  made  with  the  ordinary  quantity  of 
ether,  and  a  cotton  produced  at  a  low  temper- 


38 


ature.^  On  the  other  hand,  the  use  of  a  large 
quantity  of  alcohol  is  equivalent  to  the  use 
of  a  cotton  made  at  a  high  temperature. 
The  knowledge  of  these  facts  enables  us  to 
employ,  with  success,  cotton  which  other- 
wise we  wrould,  perhaps,  condemn  as  useless. 
Thus,  when  a  collodion  made  with  equal  quan- 
tities of  the  solvents,  gives  a  wavy  and  con- 
tractile film,  an  addition  of  strong  alcohol  may 
improve  it  and  bring  it  to  the  proper  condi- 
tion. If,  on  the  contrary,  the  film  was  too 
short  and  rotten,  a  larger  quantity  of  ether 
would  give  more  toughness  and  cohesion  to  it. 

The  purity  or  strength  of  the  solvents  has, 
also,  an  influence  on  the  state  of  the  film. 
Alcohol  and  ether,  of  a  high  specific  gravity, 
contain  much  water,  and  their  use  should  be 
avoided.  An  excess  of  water  in  the  collodion 
is  very  injurious.  It  thickens  it  and  makes 
it  flow  with  difficulty,  and  it  makes  the, film 
sometimes  so  rotten  that  it  washes  off  the 
plate.  The  water  is,  also,  one  of  the  causes  of 
the  reticulated  appearance  which  the  film  pre- 
sents in  drying.  It  seems  to  be  cracked  all 
over,  and  made  up  of  a  kind  of  network  which 
deprives  the  impression  of  sharpness.  This 
effect  is  more  to  be  feared  in  cold  than  in 
warm  weather,  so  that  in  winter  more  care 
has  to  be  taken  to  procure  good  samples  of 
ether  and  alcohol  than  at  any  other  season  of 
the  year. 

Collodion  prepared  in  all  the  conditions 


39 


which  insure  success,  will,  in  being  properly 
poured  on  a  clean  glass  plate,  present  the  fol- 
lowing peculiarities.  1st.  It  will  not  run  off 
the  edges  of  the  glass ;  if  it  does,  the  quantity  of 
cotton  is  too  small.  2nd.  It  will  give,  when 
dry,  a  transparent  film  free  from  cracks.  If  the 
film  is  semi-opaque  or  cracked,  it  indicates 
either  that  the  cotton  is  of  bad  quality,  or  that 
the  collodion  contains  an  excess  of  water. 
The  cotton  which  gives  a  semi-opaque  and 
cracked  film,  is  the  one  made  with  weak  acids 
at  a  high  temperature,  and  which  is  partly  de- 
composed by  the  acids.  3rd.  It  will  flow 
evenly,  giving  a  film  without  waves.  If  not, 
the  cotton  is  of  the  glutinous  variety,  or  in  too 
large  a  quantity,  and  one  of  the  remedies  given 
above  will  have  to  be  applied.  4th.  It  must 
be  adherent  to  the  glass,  and  tough  enough  to 
bear  a  slight  rubbing  when  it  has  set. 

A  plain  collodion  being  obtained,  which 
possesses  the  qualities  just  enumerated,  the 
next  thing  is  to  charge  it  with  a  certain 
quantity  of  iodide  and  bromide. 

Collodion  sensitized  with  iodide  alone,  will 
often  give  images  in  which  the  high  lights 
are  very  dense  by  transmitted  light,  and  the 
middle  tints  deficient  by  reflected  light.  Such 
collodion  is  made  with  cotton  possessing  the 
intense  qualities  to  an  extreme  degree,  and  is 
more  suitable  for  negatives  than  for  positives. 
If  to  such  a  collodion  a  small  quantity  of 
bromide  is  added,  the  high  lights  will  become 


40 


less  dense  by  transmission,  and  the  relation 
between  whites  and  blacks  more  harmonious ; 
at  the  same  time,  the  duration  of  the  exposure 
in  the  camera  will  be  shortened.  This  last 
fact  is  unaccountable,  and  seems  to  be  entirely 
contrary  to  what  might  be  expected.  It  is 
known  to  a  certainty  that  iodide  of  silver  in 
presence  of  nitrate  of  silver,  is  more  sensitive 
to  the  combined  action  of  the  light,  and  a  de- 
veloping agent,  than  bromide  of  silver  in  the 
same  condition.  A  paper  prepared  with  iodide 
of  silver,  will,  under  the  influence  of  a  devel- 
oper, bring  out  an  image  with  a  shorter  ex- 
posure to  the  light  than  one  prepared  with 
bromide  of  silver.  Why  then  is  bromo-iodized 
collodion  not  less  sensitive  than  iodized  collo- 
dion, instead  of  being  more  so? 

The  effect  of  bromide  is  thus  to  reduce  inten- 
sity or  contrast,  and  increase  sensitiveness. 
With  collodion,  which  does  not,  from  the  qual- 
ity of  the  cotton,  give  very  contrasted  images, 
it  should  be  omitted,  or  only  used  in  small 
quantity. 

The  bromide  of  silver  is  more  sensitive  to 
colored  light  than  the  iodide  of  silver.  In 
the  case  of  the  iodide  of  silver,  the  action 
ceases  in  the  blue  ray  of  the  spectrum,  but 
with  the  bromide  it  reaches  into  the  green. 
In  both  cases,  however,  the  most  intense 
chemical  action  resides  in  the  indigo  and 
violet,  and  goes  on  decreasing  in  measure  as 
the  green  is  approached.    The  sensitiveness  of 


41 


the  bromide  of  silver  to  the  green  ray,  has  in- 
duced the  supposition  that  a  collodion,  sensi- 
tized with  iodide  and  bromide,  was  best  suited 
to  landscape  photography,  inasmuch  as  it 
would  reproduce  the  green  foliage.  This  belief 
is  unfounded,  however.  The  effect  produced 
by  the  green  ray  on  the  bromide  of  silver, 
is  very  small  when  compared  to  the  effect 
produced  by  the  indigo,  violet  and  actinic 
invisible  rays.  Even  if  it  were  possible 
to  obtain  suitable  collodion,  sensitized  with 
bromide  alone,  the  more  actinic  rays  would 
have  arrived  at  the  maximum  of  their  action, 
before  the  green  tints  would  have  had  time  to 
produce  an  impression  on  the  sensitive  surface. 
When  bromide  is  used  in  connection  with 
iodide,  which  is  insensible  to  the  green  ray, 
the  effect  of  the  green  tints  would  be  still  less. 
That  bromide  is  useful  in  landscape  photo- 
graphy, cannot,  however,  be  denied;  but -this 
results  from  the  property  it  possesses  to  harmon- 
ize more  the  relation  between  light  and  shade, 
or,  as  we  have  stated  above,  to  reduce  contrast. 
What  produces  the  superiority  of  bromo- 
iodized  collodion,  for  landscape  photography, 
is  not  the  sensitiveness  of  bromo-iodide  of 
silver  to  green  light,  but  its  superior  sensitive- 
ness to  feeble  emanations  of  white  light,  such 
as  those  which  are  scattered  from  even  the 
darkest  green  foliage,  and  by  which  iodide  of 
silver  fails  to  be  impressed. 

4 


42 


The  iodides  and  bromides  used  to  sensitize 
collodion  are  the  following  : 

Iodide  and  bromide  of  potassium. 

Iodide  and  bromide  of  ammonium. 

Iodide  and  bromide  of  cadmium. 

Iodide  and  bromide  of  magnesium. 

Iodide  and  bromide  of  zinc. 

A  great  difference  of  opinion  exists  as  to 
which  iodide  or  bromide  is  the  most  useful  to 
sensitize  collodion.  Some  are  said  to  give 
superior  results,  others  to  be  more  sensitive. 
A  series  of  experiments,  undertaken  to  te§t 
the  value  of  these  assertions,  proved  to  us, 
however,  that  the  bases  of  the  iodides  and 
bromides,  generally  used,  have  no  direct  effect 
on  the  beauty  of  the  results,  or  on  the  sensi- 
tiveness, if  they  are  used  in  strictly  the  same 
conditions,,  and  in  such  proportions  as  to 
bring  into  the  collodion  the  same  quantity  of 
iodine  and  bromine.  The  iodide  of  iron  makes 
exception,  as  we  will  see  further. 

Amongst  the  compounds  used  as  sensitizers, 
some  are  readily  soluble  in  the  collodion. 
These  are  the  iodides  of  ammonium,  cadmium, 
magnesium  and  zinc,  and  the  bromides  of  cad- 
mium, magnesium  and  zinc.  Others,  the  iodide 
of  potassium  and  bromides  of  potassium  and 
ammonium,  are  nearly  insoluble  in  collodion, 
made  with  concentrated  solvents.  When  re- 
quired for  use,  they  should  be  dissolved  in  a 
small  quantity  of  water,  and  added  to  the 
collodion.    If  the  solvents  are  not  very  con- 


43 


centrated,  the  salts  may  be  first  dissolved  in 
a  part  of  the  alcohol  used  to  make  the  plain 
collodion,  and  then  added  to  the  solution  of 
cotton.  This  last  way  of  operating  is  prefer- 
able to  the  other,  as  it  does  not  introduce  any 
more  water  into  the  collodion. 

Each  one  of  the  salts  used  to  sensitize  col- 
lodion does,  not  contain  the  same  quantity 
of  iodine  or  bromine ;  so  that  one  salt  will 
produce  a  smaller  amount  of  iodide  or  bromide 
of  silver  in  the  film  than  another.  The  fol- 
lowing table  gives  the  proportions  of  iodine 
and  bromine  present  in  each  one  of  the  iodides 
and  bromides  generally  used  : 

1000  parts  Iodide  of  magnesium  contain  914  parts  Iodine. 

"       "        ammonium  "  876  "  " 

"       "       "        zine  "  796  "  " 

"       "       "        potassium  "  764  "  " 

"       "       "        cadmium  "  694  "  " 

"       "  Bromide  magnesium  '*  870  "  Bromine. 

w       "       "        ammonium  *'  816  " 

«       «       "        zinc  "  714  «'  " 

«       "       M        potassium  *'  672  " 

«       «       "        cadmium  .  "  588  *  " 

Collodion  sensitized  with  the  iodides  of  am- 
monium, potassium,  magnesium  and  zinc  be- 
comes red  after  a  short  time,  and  loses  sensi- 
tiveness. This  coloration  is  due  to  the  oxida- 
tion of  the  ether  and  to  the  decomposition  of 
the  pyroxyline. 

Ether  exposed  to  the  contact  of  the  air,  and 
to  the  influence  of  light,  absorbs  oxygen,  and 
.  generates  acetic  acid.  This  acetic  acid,  com- 
bining with  the  bases  of  the  iodide,  forms  an 
acetate,  and  sets  iodine  free,  which  dissolves  in 


44 


the  liquid,  and  colors  it  yellow,  orange  or 
red,  according  to  the  degree  of  decomposition 
which  has  taken  place. 

The  decomposition  of  the  pyroxyline  is  pro- 
duced by  the  alkaline  iodides,  such  as  those  of 
ammonium,  potassium  and  sodium.  The  bases 
of  these  iodides  act  on  the  pyroxyline,  setting  pe- 
roxid  of  nitrogen  free,  which,  in  its  turn,  acts  on 
the  iodide,  and  liberates  iodine.  The  effect  of 
the  alkaline  iodides-  on  the,  pyroxyline  is  the 
same  as  that  produced  by  ammonia  and  other 
alkalies.  The  collodion  becomes  fluid  and  gives 
a  porous  film,  and  when  the  effect  goes  farther, 
becomes  rotten.  The  iodides  of  cadmium, 
zinc  and  magnesium,  on  the  contrary,  produce 
a  thickening  of  the  collodion,  immediately 
after  sensitizing,  but  have  not  the  same  de- 
composing influence  on  the  pyroxyline. 

The  decomposition  of  the  collodion  is  favored 
by  heat  and  light.  According  to  Mr.  Tiffe- 
reau,  a  collodion  which  has  been  exposed  to 
the  sun's  rays  for  a  short  time,  becomes  more 
fluid,  and  acquires  an  exalted  sensitiveness ; 
but  this  sensitiveness  is  entirely  lost  soon 
afterwards. 

We  have  seen  that  a  pyroxyline,  made  at  a 
high  temperature  and  with  weak  acids,  decom- 
poses .spontaneously  much  quicker  than  one 
made  with  strong  acids.  When  such  pyroxy- 
line is  used  in  the  manufacture  of  collodion,  it 
communicates  its  decomposing  properties  to  it. 
It  should  thus  be  used  only  with  good  neutral 


45 


ether  and  alcohol,  and  the  collodion  sensitized 
with  the  compound  least  liable  to  decompose. 

The  most  stable  amongst  the  iodides  is  the 
iodide  of  cadmium.    Collodion  prepared  with 
pure  materials,  and  sensitized  with  iodide  of 
cadmium,  will  keep  for  months  without  disqol- 
.  oring. 

Bromides  are  more  stable  than  iodides ;  a 
bromo-iodized  collodion  will  keep  longer  than 
one  which  is  sensitized  with  iodide  alone. 

The  presence  of  much  free  iodine  in  collo- 
dion affects  its  sensitiveness.  The  red  color 
can  be  removed,  and  the  sensitiveness  partly 
*  restored  by  dipping  into  it  a  strip  of  zinc,  or 
a  stick  of  metallic  cadmium.  The  zinc  or  cad- 
mium will  take  up  the  free  iodine,  and  form 
iodide  of  zinc  or  of  cadmium.  The  metal 
should  be  removed  as  soon  asj;he  collodion  is 
yellow  or  orange. 

A  small  quantity  of  free  iodine  in  the  col- 
lodion, enough  to  tint  it  yellow  or  orange,  is 
not  objectionable,  as  it  does  not  interfere  with 
the  sensitiveness.  A  well  iodized  collodion, 
which  has  slightly  turned  red,  can  even  be  used 
without  much  loss  of  sensitiveness,  in  connec- 
tion with  a  neutral  or  very  slightly  acid  silver- 
solution  of  the  full  strength.  In  such  cases, 
there  is  no  necessity  for  removing  the  color. 

Independently  of  the  state  of  the  silver 
solution  and  developing  fluid,  the  sensitive- 
ness of  the  film  of  collodio-iodide  of  silver 
depends,  1st,  On  the  absence  of  certain  retard- 


48 


ing  compounds,  such  as  iodates,  carbonates, 
xanthates,  etc.  introduced  in  the  collodion  by 
sensitizing  compounds,  prepared  in  an  im- 
proper or  careless  way. — See  Chemistry  of  Io- 
dide of  Potassium. 

2nd.  On  the  absence  of  much  free  iodine  in 
the  collodion. 

3rd.  On  the  presence  of  bromide  in  the  col- 
lodion. When  a  collodion  gives  impressions 
in  which  too  much  contrast  exists  between 
light  and  shades,  an  addition  of  a  small  quan- 
tity of  bromide  will  lessen  the  contrast,  and  at 
the  same  time  cause  the  film  to  be  impressed, 
by  a  shorter  exposure  in  the  camera. 

4th.  On  the  purity  of  the  solvents.  Ether 
which  has  been  kept  some  time  is  acid  to  test 
paper,  and  liberates  iodine  in  the  collodion. 
Alcohol  often  contains  fusel  oil,  which  has  a 
retarding  influence. 

5th.  On  the  relative  proportions  of  the  sol- 
vents. An  excess  of  alcohol  in  the  collodion, 
producing  a  soft  and  porous  film,  is  favorable  to 
sensitiveness ;  an  excess  of  ether,  making  the 
film  tough  and  penetratable  with  difficulty,  is 
unfavorable  to  it. 

6th.  On  the  quality  of  the  pyroxyline.  A  py- 
roxyline  which  gives  a  film  corresponding  to 
the  one  produced  by  the  use  of  much  alcohol, 
gives  a  more  rapid  collodion  than  one  giving 
a  tough  and  contractile  film. 

7th.  On  the  decomposition  of  the  collodion. 
As  we  have  seen,  the  presence  of  much  free 


47 


iodine  in  the  collodion  is  unfavorable  to  sen- 
sitiveness. A  loose  state  of  the  film  on  the 
contrary  is  favorable.  If  a  tough  and  contrac- 
tile collodion  is  iodized  with  an  alkaline  io- 
dide, (iodide  of  potassium,  sodium  or  ammo- 
nium,) the  decomposition  which  ensues  will 
liberate  iodine,  and  make  the  film  softer  and 
more  porous  ;  and  the  retarding  influence  of 
the  free  iodine  will  be  overcome  by  the  in- 
creased sensitiveness  produced  by  the  soften- 
ing of  the  film.  If  now  the  liberation  of  the 
iodine  be  checked  by  using  the  iodide  or 
bromide  of  cadmium  in  connection  with  the  alk- 
aline iodide,  the  result  will  be  a  collodion 
which  will  remain  colorless,  or  become  only 
yellow,  and  which  will,  after  the  alkaline  iodide 
shall  have  acted  sufficiently  on  the  pyroxyline, 
give  a  soft  and  porous  film.  In  this  case,  de- 
composition will  have  the  effect  of  increasing 
the  sensitiveness  of  the  collodion. 

8th.  Use  of  iodide  of  iron.  Iodide  of  iron, 
used  in  small  quantity  in  the  collodion,  will 
give  it  a  great  sensitiveness.  This  is  owing 
to  the  double  decomposition  which  takes  place 
between  the  iodide  of  iron  and  nitrate  of 
silver  and  by  which  are  produced  iodide  of 
silver,  and  nitrate  of  iron,  which  is  a  develop- 
ing agent. 

We  have  seen  already,  that  with  collodion 
sensitized  with  the  cadmium  compounds,  an 
addition  of  a  few  drops  of  tincture  of  iodine, 
or  hydrobromic  acid,  is  a  valuable  improve. 


48 


ment,  especially  when  a  neutral  or  a  slightly 
acid  bath  is  used.  The  addition  of  iodine,  or 
better,  of  hydrobromic  acid  is  necessary  when 
collodion  is  used,  manufactured  with  ether  or 
alcohol,  which  has  been  concentrated  by  means 
of  quick-lime.  In  this  case,  hydrobromic  acid 
will  have  to  be  added  till  the  collodion  takes  a 
yellow  color,  which  effect  only  takes  place  a 
few  hours  after  the  addition. 

Tincture  of  Iodine. — Tincture  of  iodine  is  a 
solution  of  iodine  in  alcohol.  When  the 
strongest  alcohol  is  used,  ten  parts  in  weight 
will  dissolve  one  part  of  iodine.  It  is  not  ne- 
cessary to  have  it  as  strong  for  photographic 
purposes.  It  may  be  prepared  by  dissolving 
one  drachm  of  iodine  in  four  ounces  of  alcohol, 
95  per  cent. 

Hydrobromic  acid. — The  compound  called 
by  photographers  hydrobromic  acid,  and  which 
is  a  mixture  of  hydrobromic  acid,  hydro- 
bromic ether,  etc.,  is  prepared  in  the  fol- 
lowing manner  :  Take  one  or  two  ounces  of 
alcohol,  90  per  cent,  and  add  to  it  a  quantity 
of  bromine,  sufficient  to  give  it  a  red  color. 
The  next  day  it  will  have  become  colorless ; 
then  add  bromine  again,  and  if  the  color  is 
again  removed,  continue  adding  bromine  until 
the  liquid  stays  yellow  or  red.  When  this 
arrives  all  the  alcohol  has  been  trans- 
formed. What  remains  to  be  done  is  to  re- 
move the  color  by  adding  a  few  more  drops  of 
alcohol.    The  hydrobromic  acid  acts  on  the 


49 


collodion  by  liberating  iodine.  It  is  best  to 
add  it  only  to  a  small  quantity  at  a  time,  such 
as  is  required  for  use  the  next  clay,  because 
collodion  to  which  it  has  been  added  loses  too 
much  of  its  sensitiveness  when  it  is  kept  some 
time. 

The  film  of  collodio-iodide  of*  silver,  which 
is  formed  on  the  collodionized  plate,  by  dip- 
ping it  into  .the  silver  solution,  varies  in  color 
and  appearance  according  to  the  quantity  of 
iodide  used.  A  small  quantity  of  iodide  gives 
it  a  blueish  transparent  color.  A  larger 
quantity  makes  it  white  and  translucid.  A 
larger  quantity  still  makes  it  creamy  opaque. 
When  the  collodion  contains  so  much  iodide, 
that  the  iodide  of  silver  formed  cannot  be  re- 
tained in  its  pores,  it  is  said"  to  be  aver  iodized, 
If  such  collodion  is  poured  on  to  a  glass,  and 
dipped  into  the  silver  solution,  flakes  of  iodide 
of  silver  will  come  off  and  float  in  the  bath. 
The  image  will,  also,  be  entirely  on  the  sur- 
face, and  may  be  rubbed  off,  without  the  film, 
of  pyroxyline  being  injured. 

The  white  and  translucid  film  is  the  most 
favorable.  Blueish  transparent  films  can  be 
used  with  weak  neutral  silver  solutions,  but  the 
collodion  should  not  be  colored  deeper  than 
yellow.  Creamy  opaque  films  yield  rough 
pictures,  deficient  in  middle  tints,  except  when 
acid  silver  solutions  are  used,  and  in  this  case 
the  sensitiveness  is  impaired.  Films  of  mod- 
erate thickness,  iodized  so  as  to  appear  white 

5 


50 


and  semi-opaque,  give  the  best  gradation  of 
tone,  and  are  uninjured  by  a  moderate  acidity 
of  the  silver  solution. 

The  quantity  of  bromide,  to  be  used  in  the 
collodion,  depends  on  the  character  of  the  py- 
roxyline.  This  can  only  be  ascertained  by  trial. 
The  plan  we  think  the  best  is  to  make  a 
bromo-iodized  collodion,  containing  a  rather 
large  quantity  of  bromide,  and  to  add  it  to  the 
collodion  found  to  be  faulty  until  the  desired 
effect  is  obtained. 

Iodized  Collodion. 

Plain  collodion   ,  8  oz.  fluid 

Iodide  of  ammonium  , . . . .   35  grains. 

Iodide  of  cadmium  10  grains. 

The  plain  collodion  used  in  this  formula 
should  be  of  the  kind  which  gives  a  rather 
tough  film,  as  the  large  proportion  of  iodide  of 
ammonium  it  contains  will  soon  act  on  the 
pyroxyline,  and  soften  the  film.  If  the  con- 
trast it  gives  between  whites  and  blacks  is  too 
great,  mix  it  with  a  certain  quantity  of  the 
following  bromo-iodized  collodion : 

Plain  collodion   8  oz.  fluid. 

Iodide  of  ammonium  . .  ,  35  grains. 

Bromide  of  cadmium   .40  grains. 

If  instead  of  the  iodide  of  ammonium  you 
wish  to  use  the  iodide  of  potassium,  proceed 
as  follows :  1st,  dissolve  40  grains  of  iodide 
of  potassium  in  the  smallest  possible  quan- 
tity of  water;  2nd,  pour  this  into  4  ounces  of 
alcohol,  92  per  cent,  and  shake;  3d,  add 
to  this  alcohol  4  ounces  of  sulphuric  ether, 
shake  and  let  settle ;  4th,  draw  oif  the  clear 


51 


part  by  means  of  a  syphon,  and  add  the  iodide 
or  bromide  of  cadmium ;  5th,  dissolve  into  the 
liquid  the  necessary  quantity  of  pyroxyline. 

Should  you  wish  to  substitute  any  other 
iodide  or  bromide  to  those  given  above,  it  can 
be  done  by  taking  into  account  the  quantity 
of  iodine  and  bromine  each  one  contains.  The 
following  table  will  facilitate  this : — 

35  grains  of  iodide  of  ammonium  contain  the  same  amount 

of  iodine,  as 
40  grains  iodide  of  potassium, 
44     "     iodide  of  cadmium, 
33)^  "     iodide  of  magnesium, 
38)4  "     iodide  of  zinc. 

40  grains  bromide  of  cadmium  contain  the  same  amount  of 

bromine,  as 
29  grains  bromide  of  ammonium, 
35     "     bromide  of  potassium, 
27     "     bromide  of  magnesium, 
33     "     bromide  of  zinc. 

Instead  of  using  the  sensitizing  salts  in  a 
dry  state,  it  is  sometimes  more  convenient  to 
make  an  iodizing  solution,  and  to  add  it  to  the 
collodion  till  it  gives  a  white  and  semi-opaque 
film.  Any  of  the  iodides  or  bromides  can  be  used 
for  that  purpose.  The  following  is  used  in  the 
manufacture  of  Charles  Waldack's  Positive 
and  Negative  Collodion : 

Iodizing  Solution. 


Iodide  of  ammonium  ,  4  drachms. 

Iodide  of  cadmium  .4  drachms. 

Alcohol  (95  per  cent)  3  oz.  fluid. 

Bromizing  Solution. 

Bromide  of  cadmium.  1  oz. 

Alcohol  (95  per  cent),  3  oz.  fluid 


52 


From  4  to  5  drachms  of  the  iodizing  solu- 
tion are  sufficient  to  give  to  8  oz.  of  collodion 
the  degree  of  opacity  wanted.  The  quantity 
of  bromizing  solution  to  be  added  depends,  as 
we  have  seen  already,  on  the  contrast  existing 
between  the  lights  and  shades.  This  iodizing 
solution,  containing  less  alkaline  iodide  than 
is  prescribed  in  the  first  formula,  can  be  used 
with  a  plain  collodion,  giving  a  rather  short 
and  soft  film. 

The  iodide  and  bromide  most  suitable  to 
sensitize  collodion,  which  gives  a  soft  film,  are 
the  iodide  and  bromide  of  cadmium.  The 
iodides  and  bromides  of  potassium  and  of  am- 
monium should  not  be  used,  as,  by  their  pow- 
erful action  on  the  pyroxyline,  they  would  soon 
make  the  collodion  rotten.  They  may  be  used 
with  great  advantage  to  sensitize  tough  collo- 
dion, which  they  will  bring  in  a  short  time  to 
a  porous  state,  very  favorable  to  sensitiveness 
and  intensity. 

We  will  now  give  some  formulas  #f  collodion 
most  used.  JNTone  of  these  formulas  will  hold 
good  under  all  circumstances.  The  operator 
will  have  to  use  his  own  judgement  in  com- 
pounding them,  and  if  he  has  made  himself 
well  acquainted  with  the  different  influences 
which  determine  the  character  of  the  collo- 
dion, it  will  be  an  easy  task  for  him  to  obtain 
any  effect  he  desires. 

$0.  1.— Plain  collodion  .  8  oz.^ 

Iodide  of  ammonium  32  grains. 

Bromide  of  cadmium  10  grains. 


53 


Dissolve  directly  the  iodide  of  ammonium, 
and  the  bromide  of  cadmium,  in  the  plain  col- 
lodion, and  allow  it  to  settle.  The  next  day 
it  is  fit  for  use.  When  pure  materials  are 
used,  this  collodion  will  be  of  a  straw^  color 
the  clay  after  it  has  been  made,  and  it  will 
keep  for  a  long  time,  in  good  condition,  the 
bromide  of  cadmium  counteracting  the  decom- 
posing influence  of  the  iodide  of  ammonium. 
The  film  should  not  be  too  tough,  nor  too  soft, 
but  should  possess  intermediate  qualities.  The 
cotton  should  be  of  the  intense  kind. 

ft0#  2.—- Plain  collodion ,  ,  8  oz.^ 

Iodide  of  potassium  36  grains. 

Bromide  of  cadmium  10  grains. 

Put  the  iodide  of  potassium  in  an  8  oz.  bot- 
tle, and  dissolve  it  in  as  small  a  quantity  of 
water  as  possible,  then  add  the  8  oz.  of  collo- 
dion, and  finally  the  bromide  of  cadmium. 
Or,  better  yet,  modify  the  formula  as  follows : 
make  your  plain  collodion  with  2  oz.  less  alco- 
hol, and  in  this  alcohol  dissolve  your  iodide 
of  potassium,  reduced  to  fine  powder — 

Plain  collodion  6  oz.  fluid. 

Iodide  of  potassium  3b  grains  (dissolved  in  2  oz.  alcohol.) 
Bromide  of  cadmium  10  grains. 

NO.  3. — Plain  collodion  8  oz.  fluid 

Iodide  of  cadmium.  50  grains. 

Bromide  of  cadmium  6  grains. 

This  collodion  will  keep  for  a  very  long  time 
without  decomposing.  The  plain  collodion 
should  be  of  the  kind  which  gives  a  soft  and 
porous  film,  for  the  cadmium  sensitizers  have 


54 


no  decomposing  action  on  the  pyroxyline,  but 
thicken  the  collodion,  and  make  it  more 
glutinous  than  it  was  before.  Collodion  which 
has  been  submitted  to  the  decomposing  action 
of  the  ammonia,  will  answer  very  well  for  this 
formula.  A  few  drops  of  tincture  of  iodine, 
or  hydrobromic  acid,  added  to  it  will  be  found 
useful. 

No.  4.— Plain  collodion   .  8  oz.  fluid. 


Dissolve  the  iodide  and  bromide  of  potas- 
sium together  in  the  smallest  quantity  of  wa- 
ter possible,  add  the  collodion,  shake,  and  let 
settle.  Or,  better,  make  your  plain  collodion 
with  4  oz.  ether,  and  2  oz.  alcohol,  reserving 
the  2  other  ounces  alcohol  to  dissolve  your 
iodide  and  bromide  of  potassium.  You  will 
have  thus : 

Plain  collodion  . . . . ,  6  oz. 


This  collodion  being  sensitized  with  alkaline 
iodide  and  bromide  will  have  to-  be  made  with 
cotton  giving  a  tough  film.  After  a  period  of 
about  a  week,  the  action  of  tKe  alkaline  salts 
on  the  pyroxyline  will  have  brought  it  to  the 
proper  condition. 

NO.  5. — Plain  collodion  8  oz.  fluid. 


Dissolve  the  iodide  of  potassium  and  the 


Iodide  of  potassium. . , 
Bromide  of  potassium 


40  grains. 
10  grains. 


f rains j  dissolved  in  2  oz-  alcohol.) 


Iodide  of  potassium  . . 
Iodide  of  cadmium. . . 
Bromide  of  ammonium 


.  .20  grains. 
.20  grains. 
.10  grains. 


55 


bromide  of  ammonium  in  the  smallest  quant- 
ity of  water  possible,  then  add  the  collodion,  and 
finally  the  iodide  of  cadmium,  or  dissolve  the 
iodide  of  potassium  and  bromide  of  ammonium 
in  part  of  the  alcohol  prescribed  for  the  prepa- 
ration of  the  plain  collodion.  This  collodion 
will  keep  for  a  considerable  time,  the  iodide 
of  cadmium  it  contains  giving  durability  to 
it.  It  should  be  made  with  cotton  giving  a 
rather  tough  film. 

K*0«  6. — Plain  collodion  8  oz.  fluid. 

Solution  of  bromo- iodide  of  silver,  a  sufficient  quant- 
ity to  give  a  white  and  semi-opaque  film. 

The  solution  of  bromo-iodide  of  silver  is  pre- 
pared in  the  following  way : 

Dissolve  120  grains  nitrate  of  silver  in  2 
ounces  of  water,  and  80  grains  bromide  of  po- 
tassium in  2  other  ounces  of  water,  and  mix 
these  two  solutions  together;  the  result  will 
be  a  precipitate  of  bromide  of  silver  and  the 
formation  of  nitrate  of  potash,  which  will 
remain  in  solution.  Let  the  precipitate  settle 
and  pour  carefully  the  liquid  off;  then  add 
some  distilled  water,  'shake,  let  settle,  and 
pour  the  liquid  off  again.  Repeat  these 
washings  three  or  four  times  in  order  to  re- 
move all  the  nitrate  of  potash.  Then  wash 
once  or  twice  with  alcohol  in  the  same  way  as 
with  water.  Put  the  pure  bromide  of  srker  ob- 
tained in  this  way  into  a  ten  or  twelve  ounce 
bottle,  and  add  it  to  one  ounce  of  iodide  of 
potassium  reduced  to  a  very  fine  powder,  and 


56 


8  oz.  fluid  of  alcohol,  of  ordinary  strength. 
Shake  from  time  to  time  till  the  alcohol  has 
dissolved  as  much  iodide  of  potassium  as  pos- 
sible. The  clear  liquid  is  called  a  solution  of 
bromo-iodide  of  silver. 

When  bromide  of  silver  is  dissolved  in  a 
solution  of  iodide  of  potassium,  double  decom- 
position takes  place  between  the  bromide  of 
silver  and  a  part  of  the  iodide  of  potassium, 
so  that  bromide  of  potassium  and  iodide  of 
silver  are  formed.  The  iodide  of  silver  thus 
formed  dissolves  in  the  iodide  and  bromide  of 
potassium.  The  so-called  bromo-iodide  of 
silver  is,  therefore,  an  alcoholic  solution  of 
iodide  and  bromide  of  potassium  saturated 
with  iodide  of  silver. 

It  must  be  observed,  that  the  more  water 
the  alcohol  contains  the  stronger  the  solution 
will  be ;  so  that,  if  prepared  with  95  per  cent, 
alcohol  (containing  5  per  cent,  water)  it  will 
require  a  larger  quantity  to  iodize  collodion 
than  when  prepared  with  90  per  cent,  (con- 
taining 10  per  cent,  water).  It  will  thus  be 
best  to  use  90  per  cent,  alcohol,  or  if  stronger, 
to  have  it  diluted  with  the  required  quantity 
of  water. 

Very  rapid  Collodion  with  Iodide  of  Iron. — 
We  have  seen  already  that  iodide  of  iron 
mixed  with  the  collodion  gives  it  a  high  degree 
of  sensitiveness.  We  will  here  describe  the 
process  of  Alph.  De  Brebisson,  which,  in  our 


57 


hands,  has  proved  very  successful,  as  far  as 
rapidity  of  impression  is  concerned. 

Plain  collodion   .8  oz.  fluid. 

Alcoholic  solution  of  iodide  of  silver  in  iodide  of  potassium 

enough  to  give  a  white  and  semi-opaque  film. 
Alcoholic  solution  of  iodide  of  iron  1  oz.  fluid. 

The  plain  collodion  should  be  made  with 
5  oz.  ether  and  3  oz.  alcohol. 

The  alcoholic  solution  of  iodide  of  silver  in 
iodide  of  potassium  is  made  in  the  following 
way : 

NO.  1.— Distilled  water  2  oz.  fluid 

Nitrate  of  silver.  ..  120  grains. 

Xo.  2. — Distilled  water  2  oz.  fluid. 

Iodide  of  potassium  ,  120  grains. 

Mix  these  two  solutions  together  and  wash 
the  precipitate  of  iodide  of  silver  which  is 
formed  in  several  waters,  and  finally  in  alcohol, 
just  as  is  prescribed  for  the  bromide  of  silver, 
page  55.  Now  pulverize  very  finely  one  ounce 
of  iodide  of  potassium,  add  it  to  the  iodide  of 
silver,  add  also  8  oz.  alcohol,  90  per  cent,  and 
shake.  The  clear  liquid  is  an  alcoholic  solu- 
tion of  iodide  of  silver  in  iodide  of  potassium. 
The  iodide  of  iron  is  prepared  as  follows : 

Distilled  water  2)^  oz.  fluid. 

Iron  wire  or  tacks ,  1  drachm. 

Iodine  ,  3  drachm*. 

This  combination  gives,  after  two  or  three 
days,  a  liquid  of  a  light  green  color.  Take  of 
it  one  drachm,  to  which  you  add  three  or 
four  drops  acetic  acid  and  one  oume  of  alcohol. 


58 


This  gives  an  alcoholic  solution  of  iodide  of 
iron,  which  keeps  very  well. 

This  collodion  will  have  a  red  color,  and  will 
remain  sensitive  but  a  few  days. 

The  solution  of  iodide  of  iron  may  be  added 
to  any  other  collodion  and  increase  its  sensi- 
tiveness, but  it  is  always  followed  by  the  same 
results :  total  loss  of  sensitiveness  after  seven 
or  eight  days.  Another  effect  of  the  iodide  of 
iron  is  to  make  the  collpdion  thick  like  a  jelly. 

The  iodide  of  iron  collodion  cannot  be  re- 
commended except  in  extreme  cases,  as  the 
results  it  gives  are  inferior.  The  operator 
should  also  be  cautious  not  to  use  it  in  his 
ordinary  silver  solution,  as  it  would  soon 
bring  decomposition  into  it.  The  best  is  to 
have  a  silver  solution  apart,  and  to  keep  it  ex- 
posed to  the  light  when  not  in  use. 

If  one  of  the  collodions  prepared  by  the 
above  formula  gives  a  creamy  film,  or  one 
that  is  too  transparent,  bring  it  to  that  state  of 
iodizing  which  is  white  or  semi-opaque.  The 
opacity  of  the  collodion  film  depending,  1st, 
On  the  quantity  of  iodizing;  2d,  On  the 
quantity  of  cotton,  it  can  be  increased  or 
decreased,  in  two  different  ways;  1st,  By 
increasing  or  decreasing  the  quantity  of 
iodizing;  2d,  By  increasing  or  decreasing 
the  quantity  of  cotton.  Thus,  when  the 
film  is  transparent  and  thin,  add  cotton  to 
give  it  more  opacity.  When  transparent,  and 
of  the  required  thickness,  add  iodizing.  When 


59 


It  is  opaque  and  thin,  dilute  with  plain  collo- 
dion. When  opaque  and  thick,  dilute  with 
alcohol  and  ether  in  suitable  proportions. 


CHAPTER  VII. 

The  Silver  Solution  for  Positives. 

The  materials  which  enter  into  the  silver 
solution  are  the  following:  Crystalized  or 
fused  nitrate  of  silver,  water,  iodide  of  potas- 
sium and  nitric  acid. 

Nitrate  of  Silver. — The  nitrate  of  silver  used 
should  be  the  best  that  can  be  obtained.  It  is 
a  false  economy  for  operators  to  buy  a  cheap 
article,  which  is  either  adulterated  or  carelessly 
prepared. 

Crystallized  nitrate  of  silver  is  in  the  form 
of  white  crystalline  plates.  When  dissolved 
in  water  it  should  be  neutral  to  litmus  paper. 
It  is  very  important  that  it  should  be  free 
from  organic  matter,  with  which  that  es- 
pecially crystallized  out  of  the  acid  mother 
liquors  is  often  contaminated. — See  Chemistry 
of  Nitrate  of  Silver.  When  in  this  state  it 
is  not  fit  for  use,  unless  it  be  heated  in  a 
porcelain  evaporating  dish  or  crucible,  till 
it  fuses,  and  the  organic  matter  be  decom- 
posed. 

Fused  nitrate  of  silver  (lunar  caustic)  is 
found  in  commerce  in  the  form  of  white  sticks. 


60 


When  not  adulterated  with  nitrate  of  potash, 
it  can  be  used  in  photography.  It  contains  a 
small  quantity  of  nitrite  of  silver,  which  makes 
its  solution  alkaline  to  test  paper;  but  this  is 
not  objectionable,  as  a  drop  of  nitric  acid  trans- 
forms this  nitrite  into  nitrate. 

Water. — The  water  required  to  dissolve  the 
nitrate  of  silver  must  be  pure,  free  from 
organic  matter  and  from  salts.  Distilled 
water  will  answer  the  best,  or  rain  water 
which  has  been  caught  in  an  open  jar  and 
boiled.  Also,  clean  melted  ice  and  boiled  soft 
spring  water.  Rain  water  which  comes  from 
roofs,  must  be  rejected  on  account  of  the  large 
quantity  of  organic  matter  it  contains.  The 
tests  for  pure  water  are  the  following:  1st,  If 
a  drop  is  put  on  a  clean  glass  plate,  and  evap- 
orated by  a  gentle  heat,  it  leaves  no  residuum. 
2nd,  JSTo  precipitate  or  milkiness  is  produced, 
when  a  few  drops  of  a  solution  of  chloride  of 
Barium  or  nitrate  of  Baryta  are  added  to  it.  If 
the  water  becomes  milky,  or  if  a  precipitate  is 
deposited,  it  contains  a  sulphate,  probably 
sulphate  of  lime.  3rd,  Nitrate  of  silver  pro- 
duces no  precipitate.  If  it  did,  it  would  be  a 
proof  the  water  contains  either  a  chloride  or  a 
carbonate;  a  chloride,  if  the  precipitate  be 
soluble  in  ammonia;  a  carbonate,  if  insoluble  in 
ammonia,  and  soluble  in  nitric  acid.  4th,  If  a 
few  crystals  of  nitrate  of  silver  are  added  to  it, 
and  it  is  exposed  to  sunlight  in  a  white  bottle, 


I 


61 


the  liquid  remains  colorless.  If  it  turns  brown 
or  black  it  contains  organic  matter. 

Small  quantities  of  chlorides,  carbonates,  or 
of  organic  matter,  are  not  very  objectionable 
in  water  to  be  used  to  make  a  silver  solu- 
tion. Their  presence  results  in  the  loss  of  a 
small  quantity  of  nitrate  of  silver;  quantity 
generally  too  small  to  interfere  with  the 
strength  of  the  solution. 

Iodide  of  potassium. — Such  as  is  used  in 
iodizing  collodion,  answers  for  the  silver-solu- 
tion. 

Nitric  acid. — Use  the  chemical  pure,  or  the 
ordinary;  but  let  this  be  free  from  sulphuric 
acid,  which  would  produce  sulphate  of  silver 
in  the  solution. 

The  strength  of  the  silver  solutions  generally 
made,  is  forty  grains  to  the  ounce.  Twenty 
grain  silver  solutions  are  recommended  by 
some  to  be  used  with  slightly  iodized  collodion, 
such  as  gives  a  blue  transparent  film  when 
dipped  into  the  silver  bath.  We  do  not  recom- 
mend such  a  combination,  although  it  may 
sometimes  give  good  results,  but  its  use  is 
more  difficult,  especially  in  the  development  of 
the  impression. 

The  silver  solution  is  prepared  in  the  follow- 
ing way. 


The  silver  is  dissolved  in  the  water,  and 


Neutral  crystallized  nitrate  of  silver 

Water  

Tincture  of  iodine  


.  1  oz. 

12  oz.  fluid. 
10  drops. 


62 


the  tincture  of  iodine  added  to  it.  The  iodine 
will  precipitate  in  the  form  of  iodide  of  silver, 
of  which  a  part  will  be  dissolved.  Instead  of  - 
tincture  of  iodine,  you  may  use  two  grains  of 
iodide  of  potassium,  which  will  produce  the 
same  effect. 

A  solution  of  nitrate  of  silver  dissolves  io- 
dide of  silver  to  a  certain  extent.  It  is  there- 
fore necessary,  previously,  to  saturate  the  ni- 
trate solution  with  it.  If  no  attention  is  paid 
to  this,  the  iodide  of  silver,  after  having  been 
produced  in  the  film,  would  be  partially  dissolv- 
ed. This  is  the  reason  why  iodine  or  iodide  of 
potassium  has  to  be  added,  which,  by  double  de- 
composition, changes  into  the  iodide  of  silver. 

If  the  silver  solution  has  been  made  with  wa- 
ter suspected  to  contain  organic  matter,  it  will 
be  advisable  to  expose  it  to  the  sun-light  for  an 
hour  or  so.  Light  has  no  action  on  a  solution 
of  pure  nitrate  of  silver  in  pure  water,  but  if 
any  organic  matter  is  present,  the  solution  will 
become  brown,  and  a  part  of  the  silver  will  be 
reduced  and  precipitated  in  the  state  of  a 
black  powder.  In  the  case  where  tincture  of 
iodine  is  used,  it  is  best  to  expose  the  solution 
to  the  sun-light  before  iodizing  it.  Iodine  sets 
nitric  acid  free,  and  nitric  acid  counteracts  the 
decomposition,  so  that  the  solution  would  have 
to  be  exposed  much  longer  to  the  sun-light 
before  all  the  organic  matter  be  removed. 

If  iodide  of  potassium  is  used  to  iodize  the 
silver-solution,  one  or  two  drops  of  chemically 


63 


pure  nitric  acid  will  have  to  be  added.  The 
formula  will  thus  be  as  follows : 


Neutral  crystallized  nitrate  of  silver. . .  •.          .1  oz. 

Water  -  12  oz.  fluid. 

Iodide  of  potassium  *2  grains. 

Nitric  acid  1  or  2  drops. 


The  fused  nitrate  of  silver  is  sometimes  of  a 
black  color,  owing  to  the  decomposition  of  a 
small  quantity  of  it  during  the  fusion.  In 
case  it  be  used,  the  iodizing  and  nitric  acid 
should  only  be  added  after  the  black  powder 
has  been  separated  by  filtration.  Filter 
through  Swedish  filtering  paper,  or,  better  yet, 
through  cotton.  Put  a  tuft  of  cotton  into  the 
neck  of  a  funnel,  pour  on  10  or  12  drops  of  al- 
cohol,, remove  the  alcohol  with  water,  and  then 
pour  your  silver-solution  into  the  funnel.  It 
may,  at  first,  not  filter  entirely  clear,  but  it 
will  soon  do  so.  Before  filtering  the  silver-solu- 
tion, it  is  necessary  to  let  it  settle ;  if  not,  the 
precipitate  would  soon  obstruct  the  filter. 

In  case  nitrate  of  silver  is  used,  which  is 
acid,  the  solution  should  be  first  neutralized, 
and  then  treated  in  the  ordinary  way.  An 
acid  solution  of  nitrate  of  silver  reddens, the 
blue  litmus  paper.  To  neutralize  it,  make 
the  following  solution. 

Sesqui-carbonate  of  soda  (the  one  used  for  effer- 
vescent draughts)  )4oz- 

Water  4  oz.  fluid. 

Add  of  this  a  few  drops  at  a  time,  shaking 
after  each  addition.  The  precipitate  of  car- 
bonate of  silver  will  redissolve  as  long  as  there 


64 


is  any  acid  present,  and  when  all  the  acid  has 
been  neutralized,  the  liquid  will  become 
turbid ;  it  should  then  be  filtered.  The  solu- 
tion in  this  state  is  faintly  alkaline,  but  this 
alkalinity  is  removed  by  the  small  quantity  of 
nitric  acid  which  is  added  to  it,  either  directly 
or  indirectly  through  the  iodine. 

Neutral  and  acid  silver  solutions. — Neutral 
solutions  are  those  which ,  contain  neither  free 
acids  nor  free  oxides.  They  do  not  turn  red 
the  blue  litmus  paper,  as  do  the  acid  solutions ; 
nor  clo  they  turn  blue  the  reddened  litmus 
paper,  as  do  the  alkaline  solutions. 

The  presence  of  free  nitric  acid  injures  the 
sensitiveness  of  the  film  of  collodio-iodide  of 
silver.  A  slightly  acid  bath,  such  as  the  one 
we  have  prescribed,  is,  however,  preferable  to 
a  neutral  one.  If  the  sitting-time  is  a  little 
longer,  this  disadvantage  is  amply  compensa- 
ted by  a  greater  uniformity  in  working.  A 
larger  quantity  of  acid  should  be  added  only 
when  the  pictures  obtained  are  foggy  or  covered 
with  a  veil,  and  the  operator  has  no  time  to 
apply  the  remedy  spoken  of  under  head — De- 
composition of  the  Silver  Solution. 

Decomposition  of  the  Silver  Solution. — A  pure 
solution  of  nitrate  of  silver,  in  water,  is  not 
affected  by  light ;  but  when  it  contains  organic 
matter,  it  will,  under  the  influence  of  light,  be 
decomposed,  till  all  the  organic  matter  has 
been  removed,  and  a  corresponding  quantity  of 
silver  has  been  precipitated.    Such  a  solution, 


65 


when  exposed  to  the  sun's  rays,  will  first  turn 
brown,  and  will  then  become  clear  again  by 
depositing  a  black  powder,  which  is  nothing 
but  reduced  silver. 

If  a  solution  of  nitrate  of  silver  contains 
organic  matter,  decomposition  takes  place  very 
slowly  as  long  as  it  is  kept  from  the  light ; 
but  if  it  is  exposed  for  a  short  time  to  it,  and 
then  shielded  from  its  influence,  the  decom- 
posing action  will  be  less  energetic  than  if 
it  had  been  allowed  to  remain,  but  it  will  go 
on  with  much  greater  rapidity  than  before. 

As  long  as  decomposition  is  going  on  in  a  sil- 
ver solution,  no  good  pictures  can  be  obtained, 
the  free  nitrate  of  silver,  which  is  on  the  film, 
being  reduced  all  over  the  surface  of  the  plate, 
and  covering  it  with  a  veil  of  metallic  silver. 
When  this  happens,  the  remedy  is  to  neutral- 
ize the  silver  solution  with  carbonate  of  soda, 
filter  it,  and  then  expose  it  to  the  sun-light 
till  it  has  deposited  the  reduced  silver,  and 
has  cleared  up  again.  The  necessity  for  neu- 
tralizing results  from  the  fact  that  the  reduc- 
tion of  the  nitrate  of  silver  by  the  organic  mat- 
ter is  a  great  deal  slower  in  the  presence  of 
nitric  acid. 

From  all  that  has  been  said  on  this  ques 
tion,  we  may  deduct  the  following  rules  of 
action:  1st,  Never  expose  the  solution  you 
are  using  to  the  action  of  the  light,  unless 
it  be  exposed  long  enough  to  allow  all  the 
organic  matter  to  be  removed.    2nd,  If  the 

6 


66 


,  solution  works  foggy,  neutralize  it,  expose  it 
a  sufficient  length  of  time  to  the  sunlight,  filter 
it  and  acidify  it  again  with  one  or  two  drops 
of  nitric  acid.  If  it  is  impossible  for  want  of 
time  to  apply  this  remedy,  add  nitric  acid,  4 
or  5  drops  at  a  time,  till  clear  pictures  are 
obtained.  This  counteracts  the  decomposition, 
but  will  not  put  the  solution  in  good  order,  as 
the  organic  matter  is  not  removed.  It  should 
then,  on  the  first  opportunity,  be  neutralized 
and  exposed  to  the  light.*  Organic  matter 
gains  access  into  the  bath  through  the  collo- 
dion, atmospheric  dust,  unclean  glass,  etc. 

Every  time  a  plate  coated  with  collodion  is 
dipped  into  the  bath,  a  portion  of  nitrate  of 
silver  is  transformed  into  iodide  and  bromide 
of  silver,  and  a  portion  of  the  silver  solution 
is  taken  out ;  so  that  while  the  silver  solution 
decreases  in  volume,  it  also  decreases  in 
strength.  It  will,  therefore,  be  necessary  to 
fill  up  the  bath  every  day  with  a  solution  which 

*  When  a  silver  solution  contains  a  large  quantity  of 
nitric  acid,  it  is  objectionable  to  use  carbonate  of  soda  to 
neutralize  it,  as  in  this  way  a  too  large  quantity  of  nitrate 
of  soda  gains  access  into  it.  Instead  of  carbonate  of  soda, 
use  oxide  of  silver,  and  proceed  in  the  following  way  :  To 
two  or  three  ounces  of  your  silver  solution,  add  a  solution 
of  caustic  potash  till  all  the  oxide  of  silver  is  precipitated  ;  an 
excess  of  potash  will  do  no  harm.  Then  wash  the  precipi- 
tate several  times  with  clear,  and  finally  with  distilled  water; 
pour  the  water  off  and  add  the  oxide  of  silver  to  the  silver 
solution,  which  will  dissolve  part  of  it.  It  can  then  be  fil- 
tered, and  the  remaining  oxide  of  silver  can  be  used  for 
another  neutralization. 


67 


contains  a  quantity  of  nitrate  of  silver  sufficient 
to  restore  it  to  its  original  strength.  But  that 
quantity  of  nitrate  of  silver  depends  altogether 
on  the  quantity  of  iodide  and  bromide  con- 
tained in  the  collodion  film,  and  is  difficult  to 
determine.  As  a  general  thing,  it  will  answer 
to  fill  up  a  bath  containing  40  grains  to  the 
ounce,  with  the  following  solution : 

Water  «  8  fluid  ounces. 

[Nitrate  of  silver  1  ounce. 

It  is  recommended  to  add  every  night  to  the 
silver  bath  a  quantity  of  the  above  named 
solution,  corresponding  in  volume  to  the  quan- 
tity that  has  been  taken  out.  If  you  wait  un- 
til you  have  to  add  a  large  quantity  at  a  time, 
the  condition  of  your  bath  will  change  too 
much. 

We  have  not  added  to  the  solution  used  in 
filling  up  the  bath  any  iodide  of  potassium, 
nor  any  nitric  acid.  The  quantity  of  nitrate 
of  silver  added  every  day  is  too  small  to  dis- 
solve sensibly  the  collodion  film,  so  that  the 
iodide  and  bromide  are  useless  in  making  the 
addition.  In  regard  to  the  omission  of  nitric 
acid,  it  is  to  be  observed  that  every  plate, 
coated  with  yellow  or  red  collodion,  imparts 
acid  to  the  bath,  so  that  the  supply  of*  acid  is 
always  kept  up,  and  will  even  sometimes  in- 
crease to  an  excess. 

When  the  operator  has  some  uncertainty  in 
regard  to  the  strength  of  his  silver  solution, 


68 


there  exists  an  easy  way  to  estimate  it  with 
sufficient  accuracy. 

Take  the  best  table  salt  you  can  get,  put  it 
in  a  crucible  and  warm  it  gradually  till  it  is 
red  hot.  The  salt  (chloride  of  sodium)  will 
first  crackle  and  then  fuse.  When  it  is  well 
in  fusion,  pour  it  out  on  a  stone  and  put  it  in 
well  stoppered  bottles.  The  chloride  of  sodium 
in  this  state  contains  no  water.  Take  of  it  17 
grains  and  dissolve  it  in  6  fluid  ounces  distilled 
water.  This  gives  you  a  standard  solution  of 
which  each  drachm  will  precipitate  one  grain 
of  nitrate  of  silver. 

Supposing  that  with  this  solution  you  want 
to  ascertain  the  actual  strength  of  a  bath 
which  was  originally  40  grains,  you  will  have 
to  proceed  in  the  following  way : 

Measure  exactly  J  ounce  (2  fluid  drachms) 
of  your  silver  solution  and  put  it  in  a  4  or  5 
ounce  bottle. 

Rinse  your  measure  out  with  two  or  three 
drachms  of  distilled  water  and  add  it  to  the 
two  drachms  of  the  silver  solution. 

Acidify  with  two  or  three  drops  chemically 
pure  nitric  acid. 

Add  to  it  6  drachms  of  the  standard  solution, 
shake  or  stir  with  a  glass  rod  and  let  settle. 

If  the  clear  liquid  is  made  milky  by  the 
addition  of  a  few  drops  more  of  standard  solu- 


*  Since  issuing  the  first  edition,  a  useful  little  instru- 
ment, called  the  Silver  Indicator,  has  been  introduced  to  the 
trade  by  the  Scovill  Manufacturing  Co, 


69 


tion,  the  bath  is  stronger  than  6  grains  to  \ 
oz.  or  24  grains  to  1  ounce. 

Add  thus  two  drachms  more,  shake  and  let 
settle. 

If  the  clear  liquid  is  made  milky  again  by 
a  fresh  addition  of  salt  solution,  add  one 
drachm  more,  and  continue  in  the  same  way 
till  all  the  silver  has  been  precipitated  in  the 
state  of  chloride.  In  supposing  that  this  be 
done  with  nine  drachms  of  the  standard  solu- 
tion, the  solution  tested  will  be  of  nine  grains 
to  \  ounce,  or  36  grains  to  the  ounce. 

The  testing  of  a  new  silver  solution  can  be 
done  by  means  of  an  instrument  called  hydro- 
meter, which  is  well  known  to  most  operators. 
A  solution  which  has  been  used,  and  which 
contains  nitrate  of  potash,  ammonia,  cadmium, 
etc.,  cannot  have  its  strength  in  nitrate  of  sil- 
ver determined  by  means  of  the  hydrometer, 
as  all  these  salts  add  to  the  specific  gravity. 


CHAPTER  VIII. 

Developing  Solution. 

The  materials  used  in  the  developing  solu- 
tion are  the  following : 

Protosulphate  of  iron.  Water. 

Acetic  acid,  No.  8.  Nitric  acid. 

Alcohol.  Nitrate  of  potash. 
Nitrate  of  silver. 


70 


Trotosulphate  of  Ixon. — This  salt  is  known 
in  the  trade  by  the  names  of  copperas  or  green 
vitriol.  The  common  sulphate  of  iron  requires 
recrystalizing  in  order  to  render  it  sufficiently 
pure  for  photographic  purposes. 

Water. — Distilled  water,  filtered  rain,  spring 
and  river  water  can  be  used.  It  does  not  re- 
quire to  be  as  pure  as  for  the  silver  solution, 
but  it  should  not  contain  any  chlorides,  which 
would  transform  the  nitrate  of  silver  in  inso- 
luble chloride. — See  Tests  for  Chlorides  in  Chem- 
istry of  Chlorine. 

Acetic  Acid,  No.  8. — This  acid,  as  sold  by 
stock  dealers  and  druggists,  is  generally  pure. 
It  contains  sometimes  sulphuric,  sulphurous 
or  hydrochloric  acids,  which  can  be  detected, 
the  first  by  nitrate  of  baryta,  the  two  others 
by  nitrate  of  silver.  Acetic  acid  which  has  a 
smell  of  tar  should  not  be  used. 

Nitric  Acid. — The  nitric  acid  used  in  the 
developing  solution  should  be  free  from  hy- 
drochloric acid,  which,  like  the  chlorides, 
would  transform  the  silver  in  insoluble  chlo- 
ride. The  chemically  pure  nitric  acid  should 
thus  be  used,  or  if  it  cannot  be  procured,  the 
hydrochloric  acid,  contained  in  the  common 
nitric,  should  be  precipitated  as  chloride  of 
silver,  by  adding  to  it  some  of  the  silver  solu- 
tion. To  that  effect  proceed  just  like  in  all 
other  cases  of  precipitation.  Add  a  few  drops, 
shake  and  let  settle,  then  add  a  few  more,  and 
so  on  till  no  more  precipitate  is  formed.  Some 


71 


samples  of  nitric  acid,  of  a  red  color,  contain  a 
large  quantity  of  hydrochloric  acid,  and  it 
would  be  wasting  nitrate  of  silver  to  attempt 
to  bring  them  to  a  state  fit  for  use. 

Alcohol — Alcohol  90  per  cent  will  answer 
the  purpose. 

Mtrate  of  Silver. — Use  the  same  as  for 
making  the  silver  solution. 

Nitrate  of  Potash. — None  but  the  refined 
nitre  will  answer,  as  the  common  nitre  contains 
chloride  of  potassium. 


Reduce  the  sulphate  of  iron  to  powder  in  a 
clean  mortar,  put  it  with  the  other  ingredients 
in  a  bottle,  shake  till  all  is  dissolved,  and  filter 
carefully  through  a  tuft  of  cotton. 

The  strength  of  this  solution  is  calculated 
for  an  ordinary  temperature.  In  warm 
weather,  when  the  development  proceeds  too 
rapidly,  it  may  be  diluted  with  an  equal  bulk 
of  water,  and  two  or  three  ounces  more  acetic 
acid  added  to  it,  or  the  proportion  of  proto- 
sulphate  of  iron  may  be  lessened. 

The  effect  of  the  alcohol  and  acetic  acid  is  to 
make  the  development  uniform,  by  causing 
the  solution  to  flow  evenly  on  the  plate.  The 
acetic  acid,  also,  whitens  the  lights,  and  makes 
the  shades  brighter,  and  it  cannot  be  omitted, 
or  the  image  will  not  be  clear. 


Formula  Producing  Dead  Whites. 


NO.  1.— Protosulphate  of  iron, 


40  oz.  fluid. 
4  oz.  fluid. 
.  3  oz.  fluid. 


3  oz. 


Water,  r «  

Acetic  acid,  No.  8, 
Alcohol,  


72 


The  relative  proportion  of  the  ingredi- 
ents used  in  the  developing  solution  may  be 
changed  according  to  circumstances.  If  the 
development  proceeds  too  rapidly  or  too 
slowly,  decrease  or  increase  the  quantity  of 
sulphate  of  iron.  If  the  developer  does  not 
flow  evenly  over  the  plate,  add  more  alcohol. 
If  the  picture  obtained  is  not  bright  and  clear, 
supposing  the  collodion  and  silver  solution 
to  be  in  good  order,  increase  the  quantity  of 
acetic  acid. 

The  developing  solution  given  above,  and 
all  those  in  which  the  same  compounds,  and 
no  other,  enter,  will,  in  the  course  of  few  days, 
take  a  reddish  color,  and  in  that  state  will 
work  more  evenly. 

Different  Formulas  for  Developing  Solutions. 

No.  2.— Water    1  quart. 

Protosulphate  of  iron,  1  oz. 

Acetic  acid,  No.  8,   1  oz. 

Alcohol,  ,  1  oz. 

Nitrate  of  Potash,  2  drachms. 

Silver  Solution  2  fluid  drachms. 

No.  3.— Protosulphate  of  iron,   3  oz. 

Acetic  acid,  No.  8,  3  oz. 

Alcohol,. . . ,   4  oz. 

Nitrate  of  silver,  20  grains. 

Sal  Prunella,  or  Eefined  Nitre..  oz. 

Water,  40  oz. 

NO.  4.— Water,  ,  ,  ;10  fluid  oz. 

Protosulphate  of  iron,  ,  1  " 

Acetic  acid,  No.  8,   1  " 

Alcohol,  ...    1  " 

Nitrate  of  silver,  20  grains. 

Nitrate  of  potash,  120  " 

NO.  5.— Water,  12  fluid  oz. 

Protosulphate  of  iron,.   ^  oz. 


73 


Acetic  acid,  No.  8,  1  oz.  fluid. 


Nitric  acid,. . . ,  2  dr'ms" 

N  i  trate  of  s  i  i  ver,  20  gi-a  i  us. 

Nitrate  of  potash,  ...  150  " 

XO.  6.— Water,   48  fluid  oz. 

Protosulphate  of  iron,  2  oz. 

Nitric  acid   1  drachm. 

Acetic  acid,  No.  8,   2  " 


All  these  developing  solutions  give  more 
or  less  metallic  whites,  and  develop  slower 
than  the  first  one  given.  They  will,  also,  re- 
quire a  little  longer  exposure  in  the  camera, 
owing  to  the  retarding  influence  of  the  nitric 
acid  they  contain.* 

Wherever  nitric  acid  is  used  in  the  for- 
mulas given  above,  care  should  be  taken  to 
add  it  only  after  the  sulphate  of  iron  has  been 
mixed  with  the  water.  The  effect  of  nitric 
acid  on  protosulphate  of  iron  is  to  oxidize 
end  transform  it  in  persulphate  of  iron,  which 
is  not  a  developing  agent. 

CHAPTER  IX. 

Tub  Fixing  Solution. 

The  materials  used  as  fixing  agents  are  the 
cyanide  of  potassium  and  the  hyposulphite  of 

soda. 

The  fused  cyanide  of  potassium,  although  it 

*  It  is  to  be  remarked  here  that  in  some  of  these  solutions 
the  nitric  acid  is  introduced  through  the  decomposition  of 
the  nitrate  of  silver  by  the  sulphate  of  iron. 


74 


contains  a  great  deal  of  carbonate  of  potash,  fa 
suitable.  One  drachm  of  this,  dissolved  in  four 
ounces  of  water,  will  give  a  solution  of  the 
proper  strength. 

If  hyposulphite  of  soda  is  used,  six  ounces 
should  be  dissolved  in  a  pint  of  water.  The 
hyposulphite  solution  should  not  be  used 
more  than  once,  or  it  will  give  a  grey  tinge  to 
the  whites  of  the  image.  The  cyanide  of  po- 
tassium is  generally  preferred,  because  its  use 
is  less  costly,  and  it  does  not  make  the  whites 
grayish.  Its  solution  can  be  used  as  long  as 
it  retains  its  solvent  power. 

The  operator  must  be  very  cautious  in  using 
the  cyanide  of  potassium,  as  it  is  a  deadly 
poison.  Its  contact  with  wounds  and  sores 
on  the  hands  should  be  avoided.  Its  smell,  or 
rather  the  gas  that  emanates  from  it,  when  in 
contact  with  the  air,  produces  violent  head- 
ache, and  irritation  of  the  throat.  We  may 
here  remark  that  the  best  antidote  against  the 
cyanide  is  the  protosulphate  of  iron.  The 
developing  solution,  which  is  always  on  hand, 
can  be  used  immediately,  in  case  of  accident ; 
or,  better  yet,  one  drachm  of  protosulphate  of 
iron,  dissolved  in  half  a  tumbler  of  water. 


CHAPTER  A. 


Cleaning  the  Plate. 

The  surfaces  used  for  the  product 
itive  pictures  are,  as  we  have  seen  ay, 
glass,  melainotype  plates,  and  japanned  paper. 

In  the  choice  of  the  glass  great  care  should 
be  taken ;  it  should  be  perfectly  flat,  without 
scratches,  and  quite  free  from  scoria  and  air- 
bubbles.  The  polished  plate  glass  answers 
the  best,  but  is  found  generally  too  expensive, 
and  the  best  kinds  of  window  glass  are  used 
in  its  place.  Common  window  glass  is  not 
suitable  on  account  of  the  many  air-bubbles, 
the  unevenness,  and  the  difficulty  of  cleaning 
it. 

Before  proceeding  to  clean  the  glass,  the 
sharp  edges  should  be  filed  off,  to  prevent  the 
fingers  from  being  cut,  and  the  collodion  film 
from  separating  from  the  sides.  It  is  then  to 
be  immersed  in  a  solution  of  one  part  of  nitric 
or  sulphuric  acid  in  four  or  five  parts  of  water, 
where  it  should  be  left  for  several  hours.  This 
solution  corroding  the  skin,  the  glass  should 
be  removed  out  of  it  with  a  glass  rod,  or  a 
piece  of  wood,  after  which  it  should  be  well 
rinsed  with  clean  water,  and  wiped  dry  with  a 
clean  towel.  The  towel  used  for  this  purpose 
should  be  used  for  no  other,  and  should  not  be 
washed  with  soap,  but  with  a  weak  solution  of 
carbonate  of  soda,  and  then  carefully  rinsed. 
Instead  of  wiping  the  glass  dry  with  a  towel, 


76 


it  can  be  set  to  dry  on  a  sheet  of  bibilous  pa- 
per, or  on  two  nails  driven  in  the  wall. 

The  operator  must  be  careful  not  to  set  it 
while  wet  in  a  dirty  place,  as  in  virtue  of  the 
laws  of  capillarity,  all  the  dust  it  touches  will 
settle  on  its  surface.  The  washing  of  the 
glass  is  very  important,  and  should  be  careful- 
ly attended  to,  as  the  success  of  all  the  subse- 
quent  operations  depends  upon  it.  A  glass 
which  is  well  washed  is  easy  to  clean,  but  any 
amount  of  rubbing  will  not  clean  one  which  is 
not  well  washed. 

When  a  washed  glass  is  breathed  upon,  the 
moisture  settles  upon  it  in  an  irregular  man- 
ner, affecting  the  form  of  lines  in  the  direction 
it  has  been  rubbed  dry.  If  it  were  used  in 
this  state,  these  lines  would,  in  all  proba- 
bility, interfere  with  the  action  of  the  de- 
veloping fluid,  and  be  reproduced  on  the  pic- 
"  ture. 

The  following  operation  is  designed  to  pro- 
duce a  surface  on  which  the  moisture  of  the 
breath  will  condense  uniformly.  For  this, 
prepare  a  mixture  of  rottonstone  or  polishing 
powder,  and  good  pure  alcohol.  Put  a  small 
quantity  of  this  mixture  upon  the  glass,  and 
rub  it  all  over  it  for  half  a  minute  with  a  piece 
of  canton  flannel ;  then,  before  the  alcohol  has 
had  time  to  dry,  change  your  flannel  for  a 
clean  piece,  and  continue  the  rubbing  for  a 
few  moments  longer.  Finally,  finish  gently 
with  a  clean  piece  of  buckskin. 


-77 


In  rubbing  let  your  motion  be  circular,  and  do 
not  let  the  powder  dry  on  the  plate,  but  wipe 
the  plate  dry  with  the  second  piece  of  flannel. 

The  glass  has  in  this  way  to  be  cleaned  on 
both  sides,  the  finishing  with  buckskin  on  the 
side  which  is  not  used  being  dispensed  with. 
The  rottenstone  on  the  edges  should  be  well 
wiped  off,  and  any  particles  of  powder  or  fila- 
ments of  cotton  removed  by  means  of  a  soft 
camel-hair  brush. 

While  cleaning  the  glass,  it  may  be  held 
in  a  wooden  vice,  or  in  any  of  the  plate  hol- 
ders sold  for  that  purpose;  or  it  may  be 
simply  laid  on  a  clean  piece  of  paper. 

All  glasses,  after  they  have  been  used, 
should  be  put  into  the  acidulated  water,  just 
like  the  new  ones.  Those  which  have  been 
varnished  should  be  allowed  to  remain  in  it 
till  the  film  of  varnish  scales  off. 

The  melainotype  plates  are  less  troublesome 
than  the  glass.  When  new  they  do  not  want 
any  cleaning  ;  simply  brushing  off  with  a  soft 
hair  brush,  to  remove  any  particles  of  dust,  is 
all  that  is  required,  unless  the  plate  has  been 
handled  and  touched  on  the  surface  with  the 
fingers.  In  this  case,  put  on  it  a  few  drops  of 
alcohol  and  rub  dry  with  a  piece  of  flannel. 
jNTo  rottenstone  or  scouring  material  is  required, 
as  the  surface  of  the  plate  will  not  bear  this. 
But  very  light  pressure  is  needed  in  cleaning. 

If  an  unsatisfactory  picture  has  been  made 
on  the  plate,  rub  it  off  when  it  is  yet  wet, 


78 


wash  with  clean  water,  and  wipe  with  a  silk 
handkerchief  or  a  piece  of  canton  flannel ;  it  is 
then  again  ready  for  use.  If  the  picture  is  dry 
rub  it  off  with  a  little  alcohol,  and  then  go 
through  with  the  aforesaid  process  of  washing 
and  wiping;. 

When  the  plate  has  been  varnished,  the 
varnish  must  be  dissolved  with  alcohol  and 
ether,  using  several  pieces  of  clean  flannel  till 
the  varnish  has  been  all  taken  off. 

Care  has  to  be  taken  not  to  scratch  the  me- 
lainotype  plates  in  cleaning  them.  It  should 
be  well  understood  that  they  do  not  require 
polishing.  The  object  in  cleaning  them  is  only 
to  remove  foreign  matter. 

The  Niello  paper  passes  through  the  same 
process  of  cleaning  as  the  melainotype  plate. 


CHAPTER  XI. 

Formation  of  the  Film  of  Collodio-Iodide  of  Silver. 

Having  cleaned  the  glass  the  next  operation 
is  coating  it  with  the  iodized  collodion.  This 
part  of  the  manipulation  should  be  properly 
performed,  as  much  depends  on  the  evenness  of 
the  film.  Grasp  the  plate  firmly  between  the 
thumb  and  forefinger,  holding  it  at  the  lower 
left  hand  corner,  and  after  having  dusted  it 
off  with  a  camel-hair  brush,  hold  it  as  nearly 
level  as  possible,  and  pour  a  sufficient  quan- 


79 


tity  of  collodion  in  the  middle,  then  incline  it 
down,  so  as  to  cause  the  collodion  to  flow 
toward  the  corner  by  which  it  is  held,  from 
thence  toward  the  upper  left  hand  corner,  then 
toward  the  upper  right,  and  finally  down  to 
the  lower  right,  allowing  the  excess  of  liquid 
to  pass  back  into  the  bottle.  It  is  best  now  to 
hold  the  plate  in  an  oblique  position,  moving- 
it  slowly  back  and  forth,  so  as  to  cause  the 
collodion  to  flow  together  in  one  smooth  sur- 
face. Should  you  neglect  this,  you  will  inva- 
riably have  lines  running  diagonally  across 
the  plate.  The  difficulty  of  obtaining  a 
smooth  surface  depends  greatly  on  the  collo- 
dion itself.  The  thicker  it  is,  the  more  dex- 
terity will  have  to  be  used  in  coating  the 
plate.  If  lines  should  be  formed,  notwith- 
standing the  proper  care  has  been  taken  to 
avoid  them,  the  fault  lays  with  the  collodion, 
and  it  should  be  diluted  with  ether  and  alcohol, 
or  thinned  by  one  of  the  means  we  have  de- 
scribed. 

The  bottle  which  contains  the  collodion 
should  be  wiped  at  the  mouth  before  flowing 
each  plate,  as  small  particles  of  dried  collodion, 
hanging  at  the  mouth  of  the  bottle,  will  often 
be  loosened  in  pouring  from  it,  and,  settling  on 
the  film,  will  cause  a  spot  on  the  picture. 
When  large  plates  are  flowed,  it  is  advisable 
to  pour  the  excess  of  collodion,  which  runs 
from  the  plate,  into  another  bottle,  in  order 
not  to  stir  up  the  deposit,  which  is  often  on 


80 


the  bottom.  If  the  collodion  which  has  been 
used  has  become  too  thick,  it  will  have  to  be 
thinned  with  a  little  ether. 

The  next  operation  is  to  immerse  the  col- 
lodionized  plate  into  the  silver  solution.  This 
should  not  be  done  before  the  film  is  perfectly 
set,  that  is,  when  it  is  so  dry  it  receives  the 
impression  of  the  finger  at  its  lower  end,  with- 
out sticking  to  it.  If  the  plate  were  immersed 
too  soon,  lines  would  appear  at  the  end  which 
had  been  dipped  first.  The  time  the  film  re- 
quires to  set  is  dependent  on  the  temperature 
and  on  the  quantity  of  ether  and  cotton  which 
is  in  the  collodion.  It  will  take  from  half  a 
minute  to  two  minutes. 

The  baths  holding  the  silver  solution  are 
made  either  of  gutta  percha,  stone  ware,  glass, 
or  vulcanised  ritbber.  The  gutta  percha  baths, 
not  being  made  out  of  one  piece,  soon  get  dis- 
joined and  leak.  The  gutta  percha  serais, 
also,  to  decompose  slowly  the  silver  solvrlon. 
The  use  of  vulcanised  rubber  for  batlv;  we 
think  objectionable  on  account  of  the  suifhur 
it  contains.  The  photographic  ware  baths  (Gr. 
Mathiot's  patent)  are  excellent,  and  hold  the 
solution  better  than  any  other  kind  except 
those  in  glass.  They  are  generally  made  in 
the  overflowing  style,  and  are  the  cheapest  in 
the  market.  They  should  previously  be  filled 
with  water,  to  see  if  they  are  not  cracked. 
The  stoneware  baths,  improperly  called 
porcelain,    are,    after   long  use,  more  or 


81 


less  penetrated  by  the  silver  solution  ;  they  are 
valuable,  however,  on  account  of  the  facility 
with  which  they  are  cleaned,  and  the  small 
quantity  of  solution  they  require.  The  glass 
baths  are,  of  all,  the  least  objectionable,  "but 
they  are  heavy,  and  require  a  large  quantity 
of  solution  ;  if  they  could  be  made  lighter,  and 
in  the  overflowing  style  or  pattern,  they  would 
be  the  great  desideratum. 

The  film  being  set,  place  the  plate  carefully 
on  the  dipper  and  lower  it  gradually  without 
stopping.  Any  check  of  the  plate,  while  being- 
put  into  the  bath,  will  cause  an  horizontal  line 
across  the  surface.  The  plate  must  be  left  in 
the.  bath  a  time  sufficiently  long  to  allow  all 
the  iodide  and  bromide  contained  in  the  col- 
lodion film  to  be  transformed  into  iodide  and 
bromide  of  silver.  If  taken  out  as  soon  as  the 
greasy  appearance,  caused  by  the  solution  of 
the  alcohol  and  ether,  is  gone,  as  is  recom- 
mended by  some  operators,  it  will  appear  when 
it  is  removed  from  the  tablet  to  be  developed 
a  great  deal  more  opaque  than  at  the  time  it 
was  taken  out  of  the  silver  solution.  This  is  a 
conclusive  proof  that  all  the  iodide  and  bromide 
was  not  transformed  into  iodide  or  bromide 
of  silver  during  the  immersion  in  the  bath,  and 
that  the  transformation  was  continued  after  the 
plate  was  removed  out  of  it,  at  the  expense  of 
the  nitrate  of  silver  that  was  on  the  surface  of 
the  film.  This  nitrate  of  silver  on  the  film  is 
necessary,  and  required  in  the  process  of  devel- 


82 


oping  the  impression  ;  so  that  removing  a  plate 
out  of  the  silver  solution  too  soon  weakens  the 
nitrate  of  silver  on  its^surface,  and  is  the  same 
as  using  a  bath  that  is  too  weak  ;  in  such  a  case 
the  necessary  relation  between  collodion  and 
the  silver  bath  does  not  exist,  and  no  satisfac- 
tory result  can  be  expected. 

It  is  sometimes  the  case  that  irregular  lines, 
most  visible  by  transmission,  are  produced  on 
the  end  of  the  plate  which  has  been  dipped 
first.  This  occurs  when  the  collodion  has  not 
been  well  set.  These  lines  occur  mainly  in 
weak  solutions,  and  with  collodion  which  has 
been  made  with  an  excess  of  alcohol  of  insuf- 
ficient strength. 

The  length  of  time  the  plate  has  to  remain 
in  the  solution  depends :  1st,  On  the  porosity 
of  the  film ;  2nd,  On  the  quantity  of  sensiti- 
zing; 3rd,  On  the  strength  of  the  bath;  4th, 
On  the  temperature.  Generally  from  two  to 
four  minutes'  immersion  will  answer  the  pur- 
pose. 

The  film,  sometimes,  shows  a  disposition  to 
get  loose  from  the  plate,  while  being  taken  out 
of  the  bath,  or  in  the  following  operations. 
This  want  of  adherance  may  be  produced  by 
different  causes:  1st,  Want  of  adherance  of 
the  film  to  the  glass  resulting  either  from  the 
character  of  the  cotton,  or  the  excess  of  ether 
in  the  collodion ;  2nd,  Imperfect  setting ;  3rd, 
Excess  of  acidity  of  the  silver  solution.  These 
three  causes  suggest  the  remedies  to  be  applied. 


83 


As  we  have  already  mentioned,  on  page 
62,  the  silver  solution  has  to  be  saturated 
with  iodide  of  silver  to  prevent  the  iodide  of 
silver  in  the  collodion  film  being  removed. 
Now,  the  power  of  nitrate  of  silver  to  dissolve 
the  iodide,  depending  on  the  strength  of  the 
solution,  it  is  easy  to  understand  that  a 
bath,  in  getting  weaker  by  use,  will  lose,  to 
some  extent,  its  power  to  keep  the  iodide  of 
silver  in  solution ;  it  will  then  assume  the 
form  of  needle-like  crystals,  which  will  float 
in  the  solution,  and  deposit  on  the  sides 
of  the  dish.  When  a  collodionized  plate 
is  coated  in  such  a  solution,  these  crystals 
will  also  deposit  on  the  film,  which  will  some- 
times, on  removal  from  the  bath,  appear  as  if 
it  had  been  sprinkled  with  sand.  In  the  sub- 
sequent operations  this  crystalline  deposit  is 
washed  off  or  dissolved,  leaving  the  surface 
pierced  by  a  multitude  of  small  holes,  com- 
monly known  as  pinholes. 

It  is  not  only  the  weakening  of  the  bath  by 
use  which  will  produce  this  effect.  It  has  been 
ascertained  lately,  by  .Mr.  Vogel,  that  iodide 
of  silver  is  less  soluble  in  nitrate  of  silver 
when  warm  than  when  cold ;  so  that  a  bath, 
which  in  cold  weather  will  be  free  from  the 
defect  mentioned  above,  will  be  subject  to  it 
during  hot  days.  This  also  explains  the  fact 
so  often  complained  of,  that  baths,  working 
well  in  the  morning,  produce  pinholes  later 
in  the  day. 


84 


The  remedy  for  this  difficulty  is  suggested 
by  what  we  have  just  said.  A  bath  should 
not  be  saturated  with  iodide  of  silver,  especi- 
ally when  there  is  but  a  small  volume  of  it, 
or  when  it  is  to  be  used  in  a  warm  room. 

When  the  bath  is  regularly  filled  up  with  a 
stronger  uniodized  solution  of  nitrate  of  silver, 
as  recommended  on  page  67,  it  will  very  sel- 
dom get  to  such  a  state  as  to  produce  pinholes. 
When  this  accident  does  happen,  add  a  few 
ounces  of  distilled  water,  which  will  precipitate 
a  certain  quantity  of  iodide,  then  filter  and 
add  a  quantity  of  nitrate  corresponding  to  the 
quantity  of  water  added. 

When  one  is  compelled  to  use  a  bath  in 
such  condition  for  want  of  time  and  opportu- 
nity to  apply  the  remedy,  the  crystalline  de- 
posit can  be  prevented  by  keeping  the  plate  in 
motion  while  it  is  being  coated,  or  by  coating 
the  plate  collodion  side  down,  either  by  using 
a  horizontal  bath,  or  by  inclining  the  vertical 
bath  and  plate. 

Pinholes  may  also  be  produced  by  the  pres- 
ence of  acetate  of  silver  in  the  bath,  intro- 
duced by  the  use  of  carbonate  of  soda  or 
oxide  of  silver  for  neutralizing,  and  the  sub- 
sequent, addition  of  acid.  In  this  case  a 
drop  or  two  of  nitric  acid  will  speedily  re- 
move the  difficulty.  They  are  also  supposed 
to  be  produced  by  the  use  of  old  and  decom- 
posed collodion,  or  of  collodion  made  with 
partly  decomposed  pyroxyline. 


85 


The  silver  bath  should  be  kept  covered,  to 
avoid  dust  and  evaporation.  The  dust  brings 
on  decomposition  of  the  solution,  and  the  re- 
sult is  foggy  pictures.  When  small  particles 
of  dust,  or  a  black  scum,  are  discovered  on  the 
surface  of  the  silver  solution,  they  should  be 
taken  off  with  a  strip  of  blotting  paper ;  or 
when  an  overflowing  bath  is  used,  the  solu- 
tion should  be  made  to  flow  over  into  its 
smaller  portion,  from  which  it  is  discharged 
into  the  bottle.  This  over-flowed  liquid  may 
be  used  again  after  filtering. 

The  silver  solution  should  remain  excluded 
from  the  light  as  long  as  it  is  in  use.  It  may 
be  kept  constantly  in  the  bath,  but  some  pre- 
fer pouring  it  into  a  bottle  every  night. 

Sometimes  the  silver  solution  gets  out  of 
order  without  it  being  possible  to  determine 
the  cause.  This  results,  most  frequently, 
from  uncleanliness  and  carelessness ;  dipping 
into  the  bath  plates  which  are  not  perfectly 
cleaned,  leaving  it  uncovered,  so  that  the  dust 
floating  in  the  air  is  deposited  in  it ;  exposing 
it  to  the  light  which  accelerates  the  decompo- 
sition, and  not  exposing  it  long  enough  to  allow 
it  to  terminate ;  accidental  contact  with  devel- 
oping and  fixing  solution,  etc. 

All  the  causes  enumerated  above  produce 
the  same  effect — fogging  of  the  pictures.  In 
all  these  circumstances  the  remedy  to  apply 
is  exposure  to  the  direct  sun-light  for  a  few 


86 


hours.  When  no  opportunity  exists  to  do  this, 
try  an  increased  addition  of  nitric  acid. 

In  order  to  avoid  all  interruption,  resulting 
from  solutions  getting  out  of  order,  we  would 
recommend  to  every  operator,  to  have  at  least 
two,  Mid  to  keep  the  one  exposed  to  the  light 
while  the  other  is  being  used.  With  such  an 
arrangement,  much  trouble  is  avoided ;  for  a 
solution  which  has  been  used  some  time 
always  contains  organic  matter,  which,  under 
favorable  circumstances,  will  be  decomposed. 
The  proof  of  this  is  found  in  the  fact,  which 
every  operator  can  verify,  that  a  solution 
which  has  been  worked,  discolors  under  the 
influence  of  light. 

It  has  been  proposed,  as  a  remedy  for  foggy 
baths,  to  precipitate  the  silver  by  means  of 
carbonate  of  soda,  and  to  redissolve  the  carbo- 
nate of  silver,  thus  obtained,  in  nitric  acid, 
leaving  a  small  quantity  undissolved.  By 
this  process,  the  solution  is  freed  from  the. 
alkaline  nitrates  it  may  contain,  leaving  in 
it  the  nitrates  .of  magnesium,  cadmium,  or 
zinc,  if  any  of  the  iodides  or  bromides  of  these 
metals  have  been  used.  This  remedy  might 
be  used  in  case  the  exposure  to  the  direct  sun 
light  should  fail  to  restore  the  bath.  We  will 
here  give  it  as  described  by  F.  B.  Gage,  in 
No.  1,  vol.  x.  of  Humphrey's  Journal. 

"Put  the  foggy  solution  into  a  strong  bottle, 
about  three  times  larger  than  the  bulk  of  the 
solution ;  then  pulverise  and  add  pure  bi-car- 


87 


bonate  of  soda,  until  the  silver  is  all  precipi- 
tated to  the  bottom,  in  the  form  of  carbonate 
of  silver.  If  there  is  any  acid  in  the  solution, 
the  soda  must  be  added  with  caution  (stirring, 
meanwhile,  with  a  glass  rod),  as  the  soda  will 
dissolve  " fuming,"  and  may  boil  up  and  run 
over,  to  your  loss.  After  you  have  added 
soda  until  the  silver  is  all  precipitated,*  fill  the 
bottle  with  soft  water,  stir  it  up  thoroughly 
with  the  glass  rod,  then  let  the  precipitate 
settle.  When  1  it  has  done  so,  pour  off  the 
water,  as  closely  as  you  can,  without  letting 
any  of  the  precipitate  escape.  Repeat  this 
six  or  eight  times,  so  as  to  be  sure  of  washing 
off  all  the  free  soda.  Now  drain  off  the  water 
as  closely  as  possible.  (It  would  be  well  to 
use  distilled  water  for  the  last  washing,  or  the 
kind  that  you  intend  to  make  your  bath 
with.)  After  having  drained  it  as  closely  as 
possible,  proceed  to  add  chemically  pure  nitric 
acid,  to  dissolve  the  precipitate ;  add  it,  stir- 
ring with  the  glass  rod  at  the  same  time,  aud 
with  some  caution,  as  it  will  fume  strongly; 
continue  to  add  until  the  precipitate  is  nearly, 
but  not  quite  all  dissolved.  The  solution,  at  this' 
point  of  the  proceeding,  will  probably  be 
opaque,  and'almost  inky-black.  This  need  not 
cause  any  alarm  as  it  will  filter  out  clean  and 
pure.    Then  take  a  quantity  of  dear  cotton  in 

*  Add  the  soda  until  you  are  sure  tbe  silver  is  nil  thrown 
down.  Any  excess  of  soda  will  be  carried  oF  in  the  sub- 
sequent washings,  and  will  do  no  harm. 


88 


your  hand,  hold  it  under  water  and  squeeze 
and  work  it  in  your  hand  until  it  is  thoroughly 
saturated;  then  press  out  the  superabundance 
of  water,  put  it  into  a  funnel  and  filter  the 
solution  through  it;  test  it  with  the  hydro- 
meter, and  add  water  until  it  is  of  the  right 
strength ;  wash  your  funnel,  and  put  in  some 
clear  cotton ;  filter  it  again  thoroughly,  and  it 
is  right  for  a  negative  bath.  For  positives,  it  is 
only  necessary  to  add  one  drop  of  nitric  acid, 
chemically  pure,  to  each  three"  ounces  of  the 
solution.  Baths  for  negatives,  treated  in  this 
way,  work  decidedly  clearer,  better,  and 
quicker,  than  in  any  way  I  have  ever  tried. 
It  also  gives  better  delineations  in  positives. 
The  experimenter,  by  this  method,  will  be 
astonished  at  the  amount  of  black  organic 
matter  that  will  be  found  in  the  funnel,  after 
filtering  the  first  time,  and  will  be  able  to  see 
what  fogged  his  pictures. 

"  There  are  some  points  of  importance  to  be 
attend  to  in  this  process.    They  are  these : 

"1st;  That  the  bi-carbonate  of  soda  be 
pure. 

"  2d.  That  the  resulting  precipitate  be  well 
washed,  to  free  it  from  all  soda  that  is  not 
absorbed  and  combined  with  the  silver. 

"3d.  That  the  precipitate  be  not  all  dissolved 
before  it  is  filtered. 

"If  this  part  is  not  attended  to,  you  will  lose 
all  your  labor.  The  theory  of  this  is,  that 
the  organic  matter  in-  the  bath  is  soluble  in 


89 


acid,  and  cannot  be  filtered  out  while  the  bath 
is  acid.  There  need  be  but  very  little  preci- 
pitate left  in,  as  the  least  amount  undissolved 
will  leave  the  bath  perfectly  neutral." 

It  is  the  opinion  of  some,  that  several 
samples  of  collodion,  sensitized  with  different 
salts,  cannot  be  used  in  the  same  bath.  This, 
on  investigation,  has  been  found  to  be  an 
error,  the  bases  of  the  salts  used  having  no 
action  on  the  film,  with  the  exception  of  the 
iron,  as  we  have  seen  already. 

Collodionizing  the  melainotype  plate  and 
immersing  it  into  the  bath,  are  done  writh  the 
same  facility  as  the  glass  plate.  It  has 
been  objected  by  some,  that  the  iron  plate 
would  decompose  the  silver  solution.  This, 
on  trial,  is  not  found  to  be  so,  except  by  a  very 
prolonged  immersion.  Pure  iron  has  no  effect 
on  the  nitrate  of  silver ;  but  iron  rust  decom- 
poses it.  Rusty  plates  should  thus  be  care- 
fully cleaned  before  being  used. 

The  niello  paper  being  less  dense  than  the 
solution  of  nitrate  of  silver,  cannot  be  dipped 
in  the  same  way  as  the  glass  or  melainotype 
plate.  It  is  necessary  to  stick  it  on  a  piece  of 
glass  of  the  same  size  by  means  of  a  few  drops 
of  water  or  alcohol 

The  coating  of  the  plate  may  be  done  in  the 
light,  but  the  silvering  and  developing  have 
to  be  done  in  the  dark  closet.  The  dark 
closet  should  be  lighted  either  by  artificial  or 
colored  natural  light;  gas,  oil,  or  burning  fluid 

8 


90 


will  answer;  but  as  small  a  flame  as  possible 
should  be  used.  Natural  light  is  colored  by 
transmitting  it  through  a  deep  orange  pane  of 
glass,  or  through  muslin  or  paper  of  the 
same  color. 


CHAPTER  XII. 

Exposure  in  tiie  Camera. 

After  having  removed  the  plate  out  of  the 
bath,  allow  it  to  drain  a  few  seconds  before 
putting  it  into  the  tablet  or  plate-holder.  The 
tablet  should  be  carefully  wiped  after  each  op- 
eration, if  not,  the  nitrate  of  silver,  which  has 
drained  in  the  lower  part,  and  which  has  come 
in  contact  with  the  wood,  will  flow  over  the 
plate  again,  and  produce  silvery  stains  on  the 
corners.  It  may,  also,  happen  that  it  be 
splashed  over  the  plate,  either  in  putting  it 
into  the  tablet,  or  in  removing  or  putting  back 
the  slide.  The  tablet  must  always  be  kept  in 
a  perpendicular  position,  to  prevent  the  solu- 
tion from  flowing  back,  which  would  cause  the 
same  silvery  stains. 

The  plate-holders  to  be  preferred  are  those 
with  solid  glass  corners.  Those  in  which  the 
corners  are  of  several  pieces,  sealed  in  with  glue, 
are  more  liable  to  produce  stains  than  the 
others,  and  should  be  more  carefully  wiped  It 
will  be  found  useful  to  varnish,  occasionally, 
the  plate-holders,  with  a  solution  of  gum  shel- 


91 


lac,  in  strong  alcohol.  This  will  decrease  the 
chances  of  staining,  and  Will  preserve  the 
wood  from  the  corrosive  action  of  the  silver 
solution. 

As  short  a  time  as  possible  should  be  al- 
lowed between  the  withdrawal  of  the  plate 
from  the  silver  solution  and  the  development. 
The  preliminary  arrangements  for  the  sitting 
should  thus  be  made  before  the  plate  is  ready. 
It  would  not  be  advisable,  however,  to  have 
the  subject  in  position  and  ready  to  be  taken, 
for  he  will  be  tired  before  the  plate  is  taken 
out  of  the  solution,  and  the  picture  obtained 
will  not  have  a  good  expression. 

In  giving  a  position  every  part  of  the  sitter 
should  be  arranged  in  such  a  way  as  to  be 
brought  in  focus  on  the  flat  surface  of  the 
ground  glass.  The  hands,  knees  and  feet 
should  not  be  too  much  forward,  or  they  will 
appear  out  of  proportion.  This  should  be 
attended  to,  mainly,  when  such  object  glasses 
are  used  which  have  a  curved  field,  as  far 
as  it  is  compatible  with  a  good  and  easy 
position.  In  case  the  field  of  an  object  glass 
is  too  curved,  make  only  small  images  with  it, 
and  use  a  diaphragm.  The  camera  should 
be  put  about  at  the  same  height  as  the  head 
of  the  sitter. 

The  way  the  light  should  fall  on  the  model 
depends  on  the  taste  of  the  operator.  A 
northern  side  light,  at  65  or  70  degrees  incli- 
nation, is   generally  preferred.     The  point 


92 


where  the  mod§J.  should  be  set  depends  on 
the  effect  of  light  to  be  obtained.  The  im- 
age should  stand  out  well  on  the  ground 
glass,  if  not,  only  a  flat  picture  can  be  the 
result, 

The  length  of  time  the  coated  plate  must  be 
exposed  in  the  camera,  depends— 1st,  on  the 
sensitiveness  of  the  collodion  film ;  2nd,  on  the 
strength  of  the  light ;  3d,  on  the  focal  length 
of  the  lenses  ;  4th,  on  the  quantity  of  nitric 
acid  in  the  developer.  The  melainotype 
plates,  and  the  niello  paper,  require  the  same 
sitting  time  as  does  the  glass. 

A  film  prepared  in  a  neutral  bath  is  more 
sensitive  than  one  prepared  in  an  acid  bath. 
The  more  acid  the  bath  contains,  the  less  sen- 
sitive is  the  film.  Between  the  sensitiveness 
of  a  plate  prepared  in  a  neutral  bath,  and  the 
one  prepared  in  a  slightly  acid  bath,  such  as 
we  recommend,  the  difference  is  trifling. 


CHAPTER  XIII. 

Development  of  the  Picture. 

The  development  consists  in  bringing  out 
the  latent  image  which  has  been  impressed  by 
the  light.  Several  substances  have  the  pro- 
perty of  doing  this.  The  most  important  ones 
are  the  protosulphate  of  iron,  the  pyrogallic 
acid,  and  the  gallic  acid.    They  act  in  pre- 


93 


cipitating  metallic  silver,  in  a  very  reduced 
state,  on  the  parts  of  the  film  which  have  been 
impressed  by  the  light.  The  protosulphate  of 
iron  is  the  only  one  which  is  used  in  the  pro- 
duction of  collodion  positives  ;  pyrogallic  acid 
has,  until  now,  been  used  by  the  European 
artists  in  developing  negatives,  but  the  pro- 
tosulphate of  iron  is  now  coming  more  into 
use  for  this  purpose.  The  gallic  acid  is  used 
mainly  to  develop  albumen  and  dry  collodion 
plates  and  calotype  paper. 

To  develop  an  ambrotype  or  a  melainotype 
hold  the  plate  by  one  corner,  and  pour  the  so- 
lution on  at  the  bottom  of  the  side  clasped  in 
the  hand.  Use  enough  of  the  solution  to 
cover  the  plate  instantly,  so  that  it  be  covered 
entirely  before  the  action  commences  ;  other- 
wise the  development  would  go  on  unevenly. 
The  length  of  time  required  to  bring  the  image 
out  will  vary,  and  must  be  determined  by  the 
operator.  In  supposing  the  right  time  be 
given  in  the  camera,  it  will  depend — 1st,  On 
the  temperature  of  the  atmosphere ;  2nd,  On  the 
strength  of  the  developing  agent;  3d,  On  the 
quantity  of  acid  in  the  developing  agent.  The 
warmer  the  weather,  the  stronger  the  developer 
and  the  smaller  the  quantity  of  acid,  the  more 
rapidly  the  development  proceeds.  Nitric  acid 
will  retard  the  development  much  more  than 
acetic  acid.  As  soon  as  the  image  is  entirely 
visible,  which  will  require  from  eighteen  seconds 
to  a  minute,  throw  off  the  developing  solution 


94 


and  wash  the  plate  immediately  with  clean 
water,  so  as  to  remove  every  trace  of  theviron 
salt.  This  is  most  easily  done  under  a  tap. 
i  The  appearance  of  a  melainotype  or  a  niello 
plate,  after  development,  is  somewhat  different 
from  the  one  of  a  glass  picture,  owing  to  the 
black  surface  which  is  beneath.  The  proper 
development  of  these  pictures  will  require 
some  more  practice  by  those  who  are  accus- 
tomed only  to  develop  the  ambrotype. 

It  is  advisable,  at  times,  to  vary  the  propor- 
tions of  acetic  acid  and  alcohol  in  the  develop- 
er. The  alcohol  has  the  effect  to  cause  the 
solution  to  flow  more  evenly  and  unite  with 
the  film.  The  acetic  acid  produces,  to  a  cer- 
tain extent,  the  same  effect  as  the  alcohol,  and, 
also,  brightens  the  whites,  and  preserves  the 
blacks.  If  the  acid  is  too  strong  in  the  devel- 
oper, the  reduction  is  checked,  and  the  devel- 
opment is  slow  ;  if  too  weak,  it  is  sudden  and 
violent.  In  the  first  case  it  retards  the  devel- 
opment, and  gives  a  gray  tin-foil  hue,  and  the 
surface  is  bright  and  sparkling  like  frosted 
silver ;  in  the  second  case,  the  image  is  dull 
and  without  luster,  of  a  white  color,  inclining, 
when  imperfect,  to  a  yellow  or  gray. 

All  acids  tend,  not  only  to  retard  the  devel- 
opment, but  also  to  increase  the  length  of  ex- 
posure in  the  camera.  Mtric  and  sulphuric 
acid  principally  do  so ;  acetic  acid  acts  more 
feebly.  When  too  much  nitric  acid  is  present 
in  the  developer,  or  in  the  bath,  it  will  prevent 


95 


the  deposition  of  nitrate  of  silver  in  the  shades, 
and  thus  give  a  picture  without  half  tones. 
This  is  principally  seen  when  thin  films  or 
weak  baths  are  used.  The  remedy  is  to  lessen 
the  acid  in  the  developer,  or  neutralize^  it  in 
the  bath  by  means  of  carbonate  of  soda,  or  to 
iodize  more  highly  the  collodion  and  strengthen 
the  silver  solution. 

If  the  protosulphate  of  iron  is  in  excess,  it 
will  be  difficult  to  pour  it  on  the  plate  suffi-* 
ciently  quick  before  the  action  of  developing 
begins.  In  such  a  case,  after  fixing  with  the 
cyanide,  curved  lines  will  be  seen,  such  as 
would  be  produced  by  a  wave  of  fluid  flowing 
forward,  and  resting,  for  an  instant,  at  a  par- 
ticular spot.  If  the  iron  is  too  weak,  the  de- 
velopment will  be  slow,  and  the  picture  will 
become  slightly  metallic  on  drying. 

Free  nitrate  of  silver  is  required  on  the 
plate  during  the  developing  process.  If,  after 
its  exposure  to  the  light,  the  plate  is  washed 
carefully  with  water,  no  image  will  be  brought 
out  by  the  developer.  During  the  exposure 
of  the  plate  to  light  in  the  camera,  free  nitrate 
of  silver  is  not  required,  since  a  plate  washed 
carefully  with  water,  before  its  exposure,  will 
give  an  image  if  it  is  dipped  in  the  silver  bath 
before  developing.  In  such  a  case,  however, 
it  is  necessary  to  increase  the  sitting  time ;  for 
the  free  nitrate  of  silver,  on  the  surface  of  the 
film  acts  as  an  accelerator.  The  proportion 
of  nitrate  of  silver  required  on  the  collodion 


98 


film — or,  what  is  the  same,  the  strength  of  the 
silver  solution — should  he  such  as  to  yield 
sufficient  metallic  silver  in  the  development. 
If  the  quantity  of  nitrate  of  silver  was  too  small, 
the  image  would  be  feeble  and  imperfect ;  if  too 
large,  it  would  be  too  intense  and  apt  to  be 
over  developed. 

The  rapidity  of  the  development  depends, 
in  a  great  measure,  on  the  time  the  plate  has 
been  exposed  in  the  camera.  If  over  exposed, 
the  image  will  make  its  appearance  in  a  very 
short  time,  and  will  be  too  light  before  the  de- 
velopment can  be  checked  by  the  water. 
If  under  exposed,  it  will  appear  slowly,  the 
more  delicate  half  tints  will  not  be  brought 
out,  and  the  shades  will  not  be  clear.  This 
last  effect  is  most  to  be  feared  when  there 
exists  any  tendency  to  fogging  resulting  from 
the  silver  solution  containing  organic  matter  in 
decomposition. 

An  over  exposed  plate  can,  with  some  dex- 
terity, be  developed  so  as  to  be  serviceable. 
For  that,  it  will  have  to  be  watched  closely 
%  during  the  action,  and  the  water  poured  on 
before  the  image  has  become  too  light. 
None,  however,  but  imperfect  results  can  be  ob- 
tained in  this  way. 


97 


CHAPTER  XIV. 

Fixing  the  Picture. 

The  fixing  of  the  picture  consists  in  dissolv- 
ing in  cyanide  of  potassium  or  in  hyposulphite 
of  soda,  the  iodide  and  bromide  of  silver  which 
remain  in  the  film.  The  fixing  solution  can 
be  poured  on  the  plate  and  flowed  back  and 
forth  till  the  picture  is  cleared  off,  or  it  can  be 
used  in  a  flat  dish,  or  in  a  vertical  bath. 
When  cyanide  is  used,  this  last -method  is  to 
be  preferred,  as  the  liquid  is  in  this  way  less 
exposed  to  the  action  of  the  air,  which  degages 
from  it  vapors  of  hydrocyanic  (prussic)  acid. 
The  plate  is  dipped  into  it  in  the  same  way  as 
it  is  dipped  into  the  silver  solution.  Cyanide 
should  never  be  used  in  the  dark  closet.  Be- 
fore proceeding  to  the  fixing,  it  is  very  impor- 
tant to  have  every  trace  of  sulphate  of  iron 
>  washed  off,  to  avoid  blue  marks,  which  would 
otherwise  be  formed  in  the  film. 

The  fixing  solution  should  never  be  too 
strong.  The  cyanide  mainly,  has  a  dissolving 
action  on  the  metallic  silver  which  has  been 
deposited.  A  strong  solution  can,  however, 
sometimes  be  used  with  advantage  to  darken 
an  image  which  is  slightly  too  light. 

As  soon  as  the  iodide  of  silver  has  been  dis- 
solved from  the  surface,  the  plate  should  again 
be  well  washed  with  clean  water.  If  cyanide 
of  potassium  was  left  on  it,  the  picture  would 
soon  change  to  a  brownish  hue. 

9 


98 


The  washing,  performed,  the  plate  is  ready 
to  dry,  which  can  be  done  spontaneously  or  by 
means  of  a  gentle  heat  from  an  alcohol  lamp. 

CHAPTER  XV. 

Mounting  the  Picture. 

A  glass  picture  can  be  mounted  in  various 
ways.  It  can  be  sealed  to  another  glass  by 
means  of  balsam  of  fir  in  the  same  way  as  the 
flint  and  crown  are  sealed  together  to  make  an 
achromatic  lens.  For  this,  pour  a  few  drops 
of  the  balsam  on  a  fine  plate  glass,  lay  the 
picture  on  it,  with  the  collodion  side  down,  and 
press  gently  the  two  together,  so  as  to  spread 
the  balsam  all  over  the  surface.  One  of  the 
glasses  should  then  be  coated  with  asphaltum 
varnish.  None  but  very  level  glass  plates 
can  be  used  for  this  purpose,  otherwise  the 
contact  would  not  be  perfect.  Ambrotypes 
put  up  in  this  way  are  very  permanent,  as  they 
are  preserved  from  the  influence  of  air  and 
moisture.  For  large  pictures,  which  have  to  be 
hung  up,  it  will  not  do,  however,  the  oozing  out 
of  the  balsam  forming  air-bubbles  between 
the  two  glasses.  This  is  especially  the  case 
when  they  are  exposed  to  the  heat  of  the  sun. 

The  ambrotype  can  also  be  preserved  by 
coating  it  with  benzine  or  alcohol  varnish,  and 
then  backing  it  with  a  glass  which  has  been 


99 


previously  covered  with  asphaltum  varnish, 
taking  care  to  keep  the  glasses  separated  with 
a  paper  mat.  In  this  way  the  color  should  be 
applied  before  varnishing,  and  will  show  but 
very  little  through  the  film  of  collodion. 

The  most  common  way  is  to  put  up  the  am- 
brotype  reversed,  showing  the  collodion  side 
which  is  coated  with  benzine  or  alcohol  varnish, 
and  backing  the  glass  with  asphaltum  varnish ; 
then  covering  with  a  mat  and  glass. 

Some  operators  cover  the  collodion  side  of 
the  picture  first  with  a  white  varnish,  and  then 
with  the  black  asphaltum  varnish;  but  this 
throws  down  the  whites,  and  will  in  time  prove 
very  injurious,  by  discoloring  and  cracking. 

The  pictures  on  black  surfaces  can  only  be 
put  up  reversed,  like  the  daguerreotype.  They 
should  be  coated  with  white  varnish,  and  then 
mounted  with  mat  and  glass. 

To  apply  the  benzine  varnish,  pour  it  on 
the  surface  of  the  plate,  and  let  it  run  off  at 
one  corner,  as  is  done  in  flowing  with  the  col- 
lodion. To  avoid  dust  settling  on  the  face, 
hold  the  plate  downward,  after  having  held  it 
in  a  vertical  position  for  a  sufficient  time  to 
set.  If  the  varnish  is  dirty,  filter  it  through 
filtering  paper,  taking  care  to  cover  the  funnel 
with  a  glass  plate  to  prevent  evaporation.  It 
is  not  necessary  to  use  any  heat  in  drying  good 
benzine  varnish  ;  it  dries  rapidly,  giving  a  beau- 
tiful surface.  In  using  an  alcoholic  varnish,  it 
will  be  necessary  to  warm  the  plate  slightly. 


100 


The  picture  can  be  colored,  before  applying 
the  varnish,  or  after.  In  applying  them  upon 
the  varnish  the  colors  look  more  brilliant,  but 
will  not  stand  so  well. 

Pictures  for  lockets,  breast  pins,  etc.  must  be 
taken  on  melainotype  plates  or  on  niello  pa- 
per, these  being  easily  cut  to  any  size  and 
shape. 

Positives  on  glass  can  be  transferred  to  oil 
cloth  or  on  patent  leather.  For  this,  they 
have  to  be  made  with  tough  collodion,  which 
leaves  the  plate  easily.  The  manner  of  pro- 
ceeding is  as  follows  : — The  picture  being  well 
washed,  dried  and  colored,  flow  over  it  the 
following  mixture  in  quantity  sufficient  to 
cover  it : 

Alcohol,   1  ounce. 

Nitric  acid,  <    2  drops. 

Then  pour  the  liquid  off,  lay  the  plate  flat, 
and  lay  on  it  a  piece  of  oil-cloth  or  patent 
leather  of  a  size  a  little  larger  than  the  picture. 
The  oil-cloth  or  patent  leather  should  be  pre- 
viously well  cleaned  by  means  of  a  little  flour 
and  a  piece  of  canton  flannel.  On  the  oil-cloth 
or  leather  lay  another  glass,  and  put  a  spring 
clothes-pin  on  each  corner,  so  that  the  surface 
on  which  the  picture  has  to  be  transferred  be 
pressed  between  the  two  glasses.  After  five  or 
ten  minutes  remove  the  clothes-pins,  and  the 
back  glass  and  raise  carefully  the  oil-cloth  by 
one  corner,  when  the  film  will  be  found  to  ad- 
here to  its  surface.    Then  remove  the  oil-cloth 


101 


a  little  at  a  time  and  with  great  precaution,  and 
hang  up  to  dry.  Transferred  pictures  need  no 
varnishing,  they  being  preserved  by  the  part 
of  the  collodion  film  which  is  next  to  the  glass. 


CHAPTER  XVI. 

On  Collodion  Negatives. 

We  have  seen,  in  the  introductory  chapter, 
that  a  negative  is  a  kind  of  type,  or  matrix,  by 
which  an  indefinite  number  of  positive  pictures 
on  paper  can  be  produced,  by  means  of  a  pho- 
tographic printing  process. 

It  has  been  remarked,  in  both  the  positive 
and  negative  collodion  pictures,  that  the  whites, 
when  viewed  by  transmitted  light,  are  opaque, 
and  the  blacks  transparent.  If  such  a  picture 
is  placed  on  a  piece  of  paper,  prepared  in  such 
manner  that  it  blackens  when  exposed  to  the 
action  of  light,  the  rays  of  light  will  pass 
through  the  dark  or  transparent  parts  of  the 
glass,  and  impress  the  paper;  while  in  the 
light,  or  opaque  parts,  no  reduction  will  take 
place.  Through  the  middle  tints,  the  light  will 
of  course  blacken  the  paper,  more  or  less,  ac- 
cording to  the  degree  of  transparency.  The 
picture,  thus  obtained  upon  the  paper,  will 
be  a  natural  representation  of  the  object,  as 
it  appears  to  the  eye,  and  is  termed  "a positive 
m  papery 


102 


Although  all  collodion  pictures,  made  on 
transparent  surfaces,  present  the  negative  as- 
pect as  well  as  the  positive,  yet  all  can  not  be 
used  to  produce  "positives  on  paper."  A  pic- 
ture which  is  seen  with  advantage  by  reflected 
light,  that  is  to  say,  as  a  positive,  has  never 
intensity  enough  to  give  a  good  print.  A  "positive 
on  paper,"  made  wTith  it,  will  be  very  feeble, 
or  will  be  dark  in  the  white  parts,  and  devoid 
of  definition  and  middle  tints.  Therefore  it  is 
required  that  the  deposit  of  silver  should  be 
proportionately  thicker  than  in  a  positive.  To 
give  good  positives  on  paper,  the  negative 
should  be  transparent  in  the  shades,  and  of 
such  intensity  in  the  high  lights,  that  the  light 
can  with  difficulty  be  transmitted,  and  this 
must  be  combined  with  a  natural  gradation  in 
the  middle  tints.  Such  results  are  obtained, 
1st,  by  using  collodion  made  with  pyroxyline, 
which  gives  porosity  to  the  film ;  2nd,  by  using 
a  neutral,  or  very  slightly  acid  silver  solution ; 
3rd,  by  giving  a  longer  exposure  in  the  camera ; 
4th,  by  omitting  nitric  and  sulphuric  acids 
in  the  developing  solutions  ;  5th,  by  redevelop- 
ing, strengthening  or  coloring  the  negative 
which  has  been  obtained. 

The  absolute  intensity  of  a  negative  does 
not  depend  entirely  on  the  thickness  of  the  de- 
posit of  metallic  silver,  but  to  a  great  extent  on 
the  color  it  has  when  viewed  by  transmitted 
light.  Some  negatives  are  translucent,  and  of 
a  brown  yellow ;  others  of  a  dark  bluish  black ; 


103 


others  are  grey,  etc.  It  is  easily  understood, 
that  a  brown  yellow  negative  will  be  a  great 
deal  more  opaque  to  the  chemical  rays,  than 
one  that  is  grey,  supposing  the  deposit,  in  both 
cases,  has  the  same  thickness;  so  that  often 
negatives,  having  comparatively  a  slight  in- 
tensity, will  give  very  good  positive  proofs. 

The  color  of  negatives  depends  on  so  many 
causes,  that  it  is  impossible  to  determine  them 
all.  The  condition  of  the  bath,  the  nature  of 
the  developer,  the  quantity  of  acetic  acid  con- 
tained in  the  developer,  the  presence  or  absence 
of  organic  matter  in  the  silver  bath,  the  time 
of  exposure  to  light,  are  the  principal  causes, 
~No  positive  rules  can,  therefore,  be  given,  to 
determine  whether  a  negative  is  intense  enough 
or  not.  This  can  only  well  be  seen,  when  a 
positive  has  been  produced  from  it.  A  few  days 
practice  will,  however,  teach,  on  this  particular 
part,  more  satisfactorily,  than  what  can  be 
given  in  written  instruction. 


CHAPTER  XVII. 

Collodion  for  Negatives. 

In  the  chapter  on  Positive  Collodion,  many 
things  have  been  mentioned,  which  are  also 
applicable  to  negative  collodion,  and  which  it 
would  be  useless  to  repeat. 

We  will  thus  refer  the  reader  to  what  we 


104 


have  said  on  that  subject,  and  invite  him  to 
make  a  careful  perusal  of  it  before  he  commen- 
ces the  study  of  this  chapter. 

A  negative  has  to  exhibit  in  bold  contrast 
by  transmitted  light  all  the  details  which  are 
seen  by  reflected  light  in  a  positive.  This  re- 
quires a  dense  deposit  of  silver  in  the  film, 
which  result  is  arrived  at  mainly  by  the  quali- 
ties of  the  collodion.  The  intense  qualities  of 
the  collodion  depend  on  the  pyroxyline,  and  on 
the  sensitizing. 

We  have  seen  already  in  the  chapter  on 
Positive  Collodion,  that  pyroxyline,  made  at, 
a  high  temperature,  gives  a  more  intense  col- 
lodion than  that  which  has  been  made  at  a 
lower  temperature.  The  peculiar  effect  of  an 
addition  of  bromide  to  intense  collodion  has  also 
been  spoken  of  in  the  same  chapter. 

In  preparing  collodion  for  negatives  the 
operator  should  dissolve  in  his  ether  and  alco- 
hol as  much  cotton  as  is  compatible  with  good 
flowing  qualities.  The  object  to  be  attained 
is  to  obtain  a  collodion  with  much  body,  and 
which  will  at  the  same  time  give  an  even  and 
structureless  film.  As  no  definite  proportion 
of  cotton  can  be  prescribed,  this  cannot  be  al- 
ways arrived  at  on  the  first  trial.  The  best 
way  to  proceed,  is  to  mix  the  ether  and  alcohol 
together,  and  to  put  into  it  the  cotton,  a  little 
at  a  time,  till  the  liquid  obtained  is  a  little 
thicker  than  positive  collodion,  then  to  let  it 
settle  and  to  coat  a  plate  with  it,  when  it  can 


105 


be  seen  if  more  cotton  has  to  be  added,  or  if 
the  solution  has  to  be  thinned.  The  quantity 
of  cotton  to  be  used  being  once  determined,  the 
same  proportions  can  be  adhered  to  as  long  as 
the  same  sample  lasts. 

A  plain  collodion  being  obtained  having 
body  with  good  flowing  qualities,  it  may  be 
sensitized  according  to  one  of  the  formulas 
given  in  the  chapter  on  Positive  Collodion, 
omitting  altogether  the  bromide  which  may 
be  prescribed.  After  having  allowed  it  to 
settle,  make  a  sitting. 

The  picture,  you  will  obtain  will  generally 
be  very  contrasted  and  very  intense  in  the 
high  lights,  while  no  half  tints  will  be  brought 
out.  If  so  add  a  small  quantity  of  bromide  or 
of  bromo-iodized  collodion,  which  will  reduce 
the  contrast,  and  bring  out  the  middle  tints. 
If  the  true  relation  between  lights  and  shades 
does  not  exist  yet,  add  another  small  quantity 
of  bromide,  but  be  always  careful  not  to  add 
too  much  of  it,  or  the  intensity  will  be  reduced 
to  such  an  extent  that  the  collodion  will  be 
Vcilueless  for  the  purpose  it  was  required.  An 
addition  of  ten  grains  bromide  of  cadmium  at 
a  time  to  one  pound  of  cojlodion  will  be  found 
suitable. 

It  may  be  also  that  the  collodion,  after  the 
addition  of  iodide,  gives  the  amount  of  intensity 
required,  and  no  more.  In  this  case,  of  course, 
no  bromide  should  be  added.  In  case  the 
iodized  collodion  gives  images  wanting  in  in- 


106 


tensity,  it  is  a  proof  that  the  cotton  is  not  of 
the  right  kind,  and  there  is  no  remedy  but  to 
allow  it  to  become,  old. 

The  alkaline  iodides  and  bromides  have,  as 
has  been  mentioned  already,  a  powerful  action 
on  the  pyroxyline  which  has  been  dissolved 
in  the  ether  and  alcohol.  This  action  results 
in  the  change  of  the  film  from  the  tough  and 
contractile  to  the  soft  and  porous  state.  This 
soft  and  porous  state  of  the  film  is  favorable  to 
intensity,  for  it  allows  a  dense  deposit  of  me- 
tallic silver ;  whereas,  when  a  tough  film  is 
used,  the  deposit  is  only  on  the  parts  nearer 
the  surface.  It  is  owing  to  this  action  of  the 
alkaline  iodides  and  bromides  that  a  collodion, 
which  gives  no  intensity  when  fresh,  acquires 
this  quality  by  age. 

Ammonia,  potash  and  soda  affect  the  col- 
lodion in  the  same  way,  but  with  a  great  deal 
more  energy.  A  few  drops  of  ammonia  added 
to  collodion,  which  gives  images  wanting  in  in- 
tensity, will  in  a  short  time  bring  it  to  the 
porous  state.  Such  addition  should  not  be 
made  to  collodion  sensitized  with  the  salts  of 
cadmium,  zinc,  etc.,  as  the  oxides  of  these 
metals  would  be  precipitated.  In  all  cases 
when  ammonia  has  been  added,  the  collodion 
becomes  alkaline,  and  should  be,  after  the 
action  is  fully  produced,  made  slightly  acid 
again  by  the  addition  of  a  few  drops  of  tincture 
of  iodine  or  hydrobromic  acid. 

Negative  collodion,  the  same  as  positive, 


107 


should  not  be  iodized  beyond  the  white  and 
semi-opaque  state,  and,  as  it  has  generally 
more  body,  this  state  is  attained  by  the  use  of 
a  smaller  quantity  of  iodide  than  is  required 
for  positive  collodion. 

The  intensity  of  collodion  can  be  much  in- 
creased by  the  addition  of  a  few  drops  of  an 
alcoholic  solution  of  giycyrrhizine,  or  liquorice 
sugar.  It  is,  however,  not  advisable  for  con- 
stant use,  as  it  tends  to  bring  decomposition 
in  the  bath. 


CHAPTER  XVIII. 

The  Silver  Solution  for  Negatives. 

The  presence  of  free  nitric  acid  in  the  silver 
solution  counteracting  the  reduction  of  silver  on 
the  film  makes  it  necessary  to  have  the  solution 
for  negatives  as  little  acid  as  possible.  Great 
care  should  thus  be  taken  to  procure  a  sample 
of  good  nitrate  of  silver.  Nitrate  of  silver, 
which  contains  free  acicl,  is  generally  contam- 
inated also  with  a  substance  which  is  the  result 
of  the  action  of  nitric  acid  on  organic  matter. 
The  presence  of  this  substance  is  very  unfavor- 
able to  intensity,  and  can  only  be  removed  by 
fusing  the  nitrate  of  silver  before  dissolving  it, 
or,  when  it  is  in  solution,  by  neutralizing  and 


V 


108 


exposing  to  the  light.  The  following  is  the 
formula  for  the  negative  silver  solution : 


Dissolve  the  nitrate  of  silver  in  eleven 
ounces  of  the  water,  and  the  iodide  of  potas- 
sium in  the  remaining  ounce,  and  add  the  two 
solutions  together,  after  which  let  settle,  and 
filter  the  clear  part. 

The  solution  obtained  in  this  way  is  per- 
fectly neutral,  and  is  very  likely  to  give  misty 
pictures.  It  has  to  be  made  very  slightly  acid, 
just  enough  to  produce  clear  shades.  One  drop 
of  nitric  acid  might  be  too  much.  Instead  of  ad- 
ding nitric  acid  of  the  ordinary  strength,  it  is 
best  to  use  a  solution  of  ten  drops  of  the 
chemically  pure  to  one  ounce  of  water,  and  to 
add  of  this  solution  one  or  two  drops  at  a  time, 
till  the  pictures  obtained  are  clear  in  the 
shadows.  Instead  of  nitric  acid,  acetic  acid 
can  also  be  used. 

The  strength  of  this  bath  should  be  kept  up 
by  the  addition  of  a  solution  of  one  ounce 
of  nitrate  of  silver  in  eight  ounces  of  water. 

The  use  of  dark  colored  collodion  develops 
nitric  acid  in  the  bath.  When  such  collodion 
has  been  used,  and  the  appearance  of  the 
negatives  is  pale,  and  without  the  required  in- 
tensity, the  solution  has  to  be  tested,  and  if 
found  very  acid,  neutralized  by  the  addition  of 
a  few  drops  of  a  solution  of  carbonate  of  soda, 


Neutral  nitrate  of  silver. 

Water  

Iodide  of  potassium,  . . . 


1  oz. 
12  oz.  fluid. 

,  2  grains. 


109 


until  the  liquid  becomes  permanently  turbid, 
It  should  then  be  filtered  and  made  faintly 
acid  again  by  adding  a  little  of  the  solution  of 
nitric  acid. 


CHAPTER  XIX. 

The  Developing  Solution. 

Two  different  substances  are  used  to  develop 
collodion  negatives  ;  the  protosulphate  of  iron 
and  the  pyrogallic  acid.  Each  of  these  devel- 
oping agents  possesses  advantages  peculiar  to 
itself.  The  protosulphate  of  iron  requires  only 
about  one-half  of  the  exposure  which  is 
required  when  the  pyrogallic  acid  is  used,  but 
it  is  more  difficult  to  produce  a  sufficient 
amount  of  intensity  with  the  former  than  with 
the  latter.  The  protosulphate  of  iron  develops 
very  rapidly,  the  pyrogallic  acid  develops 
slowly.  The  time  of  exposure  to  light  must 
be  calculated  with  greater  accuracy  when  the 
sulphate  of  iron  is  used,  because  the  develop- 
ment, being  very  rapid,  cannot  be  checked 
when  the  sitting  has  been  too  long,  nor  can  it 
be  pushed  further  when  it  has  been  too  short. 
When  developing  with  pyrogallic  acid,  on  the 
contrary,  the  development  can  be  checked  with 
more  facility ;  and  when  too  short  a  sitting  has 
been  given,  the  bringing  out  of  the  picture  can 
be  " pushed."    But  from  this  the  operator 


110 


must  not,  however,  conclude  that  the  time  of 
sitting  is  not  of  much  importance  in  the  latter 
case  ;  the  advantage  gained  with  the  pyro- 
gallic  acid  is,  that  he  has  more  latitude  in  the 
lime  of  exposure. 

Tht-  sulphate  of  iron  developer  is  prepared 
as  follows : 


The  quantity  of  the  iron  salt  can  be  reduced 
in  warm  weather  when  the  development  pro- 
ceeds too  rapidly,  or  the  quantity  of  acetic 
acid  can  be  increased. 

Pyrogallic  acid,  although  termed  an  acid,  is 
a  strictly  neutral  substance,  and  would  act  with 
too  much  violence,  and  produce  decomposition 
of  the  silver  salt  all  over  the  plate,  if  a  cer- 
tain quantity  of  acetic  acid  was  not  added  to  it. 

Prepare  its  solution  according  to  the  follow- 
ing formula : 

Water,. .   -   1  ounce  fluid. 

Pyrogallic  acid,. .  . .  ,   —  2  grains. 

Alcohol,   1  drachm. 

Acetic  acid,  No.  8   1 

In  warm  weather,  the  quantity  of  acetic  acid 
may  be  increased,  and  in  cold  weather  it  may 
be  diminished,  or  the  proportion  of  pyrogallic 
acid  increased.  The  alcohol  is  added  to  make 
the  solution  flow  more  evenly  over  the  plate. 
This  solution  decomposes  after  a  few  days,  and 
becomes  brown,  so  that  it  is  advisable  to  make 


Protosulphate  of  iron, 

Water,  

Acetic  acid,  No.  8. . . 
Alcohol,  


,  3  ounces. 
.40  ounces. 
.  4  ounces. 
.  3  ounces. 


Ill 


only  a  small  quantity  at  a  time.    If,  however, 

it  is  made  four  or  five  times  more  concentrated 
than  is  required  for  me,  it  will  keep  longer. 
In  such  cases  it  can  be  diluted  with  pure  water 
as  required. 

The  water  used  for  the  developer  is  required 
to  be  pure  soft  spring,  rain,  or  distilled  water. 


CHAPTER  XX. 

The   Fixing  Solution. 

Any  of  the  two  fixing  solutions  employed 
for  positives  can  be  used  for  negatives.  We 
prefer  always  using  cyanide  of  potassium,  it 
being  more  economical  and  easier  washed  from 
the  plate  than  the  hyposulphite  of  soda.  In 
its  use,  observe  that  it  be  diluted  to  such  a 
point;  that  it  will  dissolve  the  unreduced  iodide 
of  silver,  without  attacking  the  film  itself. 
Negatives,  developed  with  pyrogallic  acid,  are 
more  easily  attacked  by  the  cyanide,  than 
those  developed  with  protosulphate  of  iron. 
If,  however,  the  cyanide  takes  more  than  half 
a  minute  to  fix  a  whole  size  plate,  no  fear  need 
be  entertained  in  regard  to  its  use,  when  the 
pyrogallic  acid  is  employed  in  developing. 


112 

CHAPTER  XXI. 

Practical  Details   of  the  Negative  Process. 

It  will  not  be  necessary  to  say  anything  in 
regard  to  the  formation  of  the  film  of  collodio- 
iodide  of  silver  in  the  negative  process,  it 
being  exactly  the  same  as  in  the  positive  pro- 
cess. 

The  exposure  to  light  of  a  negative  is  never 
less  than  twice  the  time  required  to  make  a  posi- 
tive. The  rule  is,  to  give  such  a  length  of  time 
that  after  development  the  feeblest  radiations 
are  marked  by  transmitted  light.  With  py  ro- 
gallic  acid  it  requires  about  three  times  longer 
exposure  in  the  camera  than  with  the  iron  salt. 

As  regards  the  development  of  the  picture, 
it  is  about  the  same  as  with  positives,  when 
protosulphate  of  iron  is  used ;  but  somewhat 
different  with  pyrogallic  acid.  In  the  produc- 
tion of  positive  pictures  it  is  necessary  to  stop 
the  development  at  a  certain  stage  in  order 
to  have  good,  clear  shadows ;  when  nega- 
tives are  required,  the  development  must  be 
carried  to  its  utmost  limits,  provided  the  sit- 
ting time  has  been  given  right.  This  is  the 
case  both  with  protosulphate  of  iron  and  with 
pyrogallic  acid. 

"  The  development  with  the  protosulphate  of 
iron  is  easier  and  quicker,  the  image  appear- 
ing almost  immediately.  It  is  important  not 
to  throw  the  developer  off  too  soon,  but  to  let 
it  remain  till  no  further  change  is  produced. 


113 


If,  after  being  developed,  the  image  has  not 
sufficient  intensity  to  give  good  prints,  it  must 
be  redeveloped  or  strengthened.  The  strength- 
ening is  done  after  the  image  has  been  washed 
and  fixed.  (See  Chapter  22.)  The  redevelop- 
ing is  done  before  exposing  the  plate  to  the  light. 
Several  methods  are  in  use. 

1st.  Redevelopment  with  nitrate  of  silver  and 
protosulphate  of  iron. — Your  image  being  fully 
developed,  pour  the  solution  off  and  let  the 
plate  drain  a  moment.  Then  pour  over  it  a 
mixture  of  one  part  of  your  silver  solution  and 
three  parts  of  distilled  water,  in  quantity  suf- 
ficient to  cover  it.  Move  back  and  forth  with 
dexterity,  so  as  to  have  the  action  equal  all 
over  the  plate,  pour  the  excess  off,  and  spread 
your  developing  solution  over  the  plate  again. 
During  each  of  these  two  operations  metallic 
silver  is  reduced  on  the  parts  where  a  deposit 
has  not  already  taken  place,  and  thus  makes 
them  more  opaque.  If  sufficient  intensity  is 
not  obtained  after  a  first  redevelopment,  repeat 
the  same  operations. 

2nd.  Redevelopment  ivith  pyrogallic  acid  and 

nitrate  of  silver. — Wash  your  plate  well  so 

that  no  sulphate  of  iron  remains  in  the  film, 

after  which  you  pour  over  it  enough  of  the 

pyrogallic  acid  developer  as  is  necessary  to 

cover  the  plate  ;  move  back  and  forth  so  that 

the  solution  unites  well  with  the  film  and  pour 

it  off  into  a  small  glass  ;  then  add  from  five 

to  ten  drops  of  your  silver  solution,  pour  the 
10 


114 


solution  on  again,  and  keep  the  plate  moving 
till  a  sufficient  quantity  of  silver  has  been  de- 
posited. If  more  intensity  is  required,  repeat 
the  same  operations. 

3rd.  Redevelopment  with  gallic  acid  and  ni- 
trate of  silver. — Operate  entirely  in  the  same 
way  as  when  pyrogallic  acid  is  used.  The  so- 
lution of  gallic  acid  for  redeveloping  is  as  fol- 
lows : 

Saturated  solution  of  gallic  acid,   1  ot.  fluid. 

Acetic  acid,  No.  8 .   1  drachm. 

Alcohol,   1  drachm. 

When  developing  with  pyrogallic  acid,  hold 
the  plate  by  one  corner,  and  pour  on  the  de- 
veloping fluid  in  quantity  sufficient  to  cover 
the  whole  surface.  After  one  or  two  minutes 
the  image  will  have  come  out  in  all  its  details; 
If  this  image  is  not  intense  enough,  take  a 
fresh  quantity  of  the  developing  solution,  add 
to  it  five  or  ten  drops  of  the  silver  solution 
and  pour  over  the  plate  again.  Repeat  the 
same  thing  till  the  image  has  attained  the  re- 
quired intensity.  The  glass  that  has  contained 
the  mixture  of  pyrogallic  acid  and  nitrate  of 
silver  should  be  carefully  washed  out  after 
each  operation,  or  the  black  deposit  that  forms 
in  it  will  cause  the  fresh  solution  to  decompose. 

Redevelopment  with  nitrate  of  silver,  protosul- 
phate  of  iron  and  tartaric  acid. — A  method  of 
redeveloping  by  adding  a  few  drops  of  silver 
to  the  ordinary  developer,  and  flowing  it  again 
over  the  plate,  has  been  and  is  yet  in  use  to 


115 


some  extent.  The  objection  to  it  is,  that  the 
solution  gets  muddy  in  a  very  short  space  of 
time,  hj  the  silver  being  precipitated.  By 
adding  to  the  mixture  of  sulphate  of  iron  and 
nitrate  of  silver  a  few  drops  of  saturated  so- 
lution of  tartaric  acid,  the  liquid  will  remain 
clear,  and  all  the  silver  it  contains  will  be 
deposited  on  the  developed  image. 

The  redeveloping  solution  can  be  prepared 
according  to  the  following  formula  : 

Water,   1  ounce. 

Sulphate  of  iron,  20  grains. 

Tartaric  acid,   6  grains. 

Add  a  few  drops  of  silver  solution  when 
leady  to  use  it.  This  method  of  intensifying 
requires  no  previous  washing. 

The  redeveloping  of  the  negative  can  be 
done  also  after  the  fixing.  In  the  following 
chapter  we  describe  some  methods  of  intensi- 
fying, which  can  only  be  applied  after  fixing. 

A  plate  which  has  not  been  exposed  long 
enough  to  the  light  develops  slowly.  If  de- 
veloped with  pyrogallic  acid,  and  much  silver 
solution,  the  high  lights  are  found  to  be  very 
opaque,  and  the  shadows  transparent ;  but  the 
half  tones  are  not  well  marked.  When  pro- 
tosulphate  of  iron  has  been  used,  the  image 
will  have  the  same  appearance,  except  that 
the  silver  will  not  be  reduced  as  much  on  the 
high  lights. 

When  a  negative  has  been  over-exposed, 
the  development  proceeds  rapidly,  and  no  dis- 


116 


tinct  image  can  be  seen  by  reflected  light; 
viewed  by  transmitted  light  there  is  a  want  of 
proper  contrast  between  the  high  lights  and 
the  shadows,  so  that  the  picture  appears  flat. 

After  the  image  has  been  developed,  the 
plate  must  be  washed,  and  the  fixing  done  in 
the  same  way  as  for  positives. 

The  negative  requires  to  be  preserved  by  a 
coating  of  gum  arabic  or  varnish,  to  prevent 
it  from  being  scratched  during  the  printing. 
When  but  few  prints  are  to  be  made  from  it, 
and  it  is  to  be  handled  by  a  careful  printer, 
the  gum  arabic  solution  will  answer  all  pur- 
poses. This  is  made  by  dissolving  by  heat  one 
ounce  of  gum  arabic  in  ten  ounces  of  wrater, 
and  filtering.  It  is  applied  on  the  negative 
before  it  is  dry,  after  it  is  well  drained  of  the 
excess  of  water. 

Varnishing  the  negative  reduces  its  inten- 
sity. Thin  varnish  has  this  effect  less  than 
the  thick.  It  is  advisable  in  all  cases  to  use 
the  gum  arabic  solution  first,  as  the  negative 
is  then  made  less  transparent  by  the  varnish. 

The  varnishes  in  the  market  are  made 
either  with  alcohol  or  benzine.  Alcohol  var- 
nishes require  heat  in  drying,  with  the  excep- 
tion of  Anthony's  flint  varnish,  which  is 
made  writh  ammoniated  alcohol ;  benzine  var- 
nishes, on  the  contrary,  dry  without  heat. 

The  gums  used  in  the  preparation  of  alco- 
hol varnishes  are  the  white  or  the  shellac,  9 
mixed  with  a  small  quantity  of  sandarac  or 


117 


mastic.  Those  used  in  the  preparation  of 
benzine  varnishes  are  the  gum  dammar,  copal 
or  amber.  The  two  first  will  not  answer,  as 
they  give  a  film  which  is  sticky.  Amber 
alone  furnishes  a  varnish  which  answers  the 
purpose.  It  gives  a  film  almost  as  hard  as  the 
glass  itself,  and  which  is  not  liable  to  crack. 
Negatives  varnished  with  it,  will  stand  a 
greater  amount  of  rough  use  than  those  pre- 
served by  any  other  preparation.  The  amber 
and  benzine  varnish  is  known  in  the  trade  as 
the  Adamantine  Varnish. 


CHAPTER  XXII. 

Strengthening  of  the  Negative. 

It  is  often  the  case,  more  especially  when 
the  protosulphate  of  iron  has  been  used  as  a 
developing  agent,  that  the  negative  obtained, 
although  all  the  feeblest  radiations  are  im- 
pressed, has  not  intensity  enough  to  yield 
good  positives,  in  which  case  it  must  be  sub- 
mitted to  a  process  by  which  the  intensity  is 
increased.  This  object  is  attained  by  rede- 
veloping or  by  strengthening. 

Before  proceeding  it  may  be  well  to  under- 
stand the  difference  between  the  terms  rede- 
veloping and  strengthening.  Redeveloping, 
as  is  indicated  by  the  name,  means  to  increase 
the  intensity  of  the  negative  by  repeating  the 
operations  of  the  development.  Strengthening 


118 


means,  to  increase  the  intensity,  by  other 
processes.  We  have  already  described  in  the 
previous  chapter  the  processes  of  redeveloping. 
This  chapter  will  treat  specially  of  the  processes 
of  strengthening.  Several  methods  are  in  use. 

1st.  Treatment  of  the  image  by  sulphuret  of 
potassium,  or  any  other  alkaline  sulphuret. — This 
is  the  most  convenient  mode  of  strengthening, 
when  but  little  has  to  be  added  to  the  inten- 
sity. Dissolve  one  ounce  of  sulphuret  of  potas- 
sium in  half  a  pint  of  water,  filter  it  and  keep 
it  in  a  corked  bottle.  Fix  the  negative,  wash 
it  carefully,  and  pour  this  solution  over  it. 
The  color  will  change  to  a  bluish  black  by  trans- 
mitted light.  When  the  action  has  gone 
through  the  film,  wash  carefully,  gum,  and  let 
dry.  By  this  process  the  metallic  silver  is 
changed  into  sulphuret  of  silver.  The  film  is 
not  made  much  denser,  but  more  impermeable 
to  the  chemical  rays. 

2nd.  Treatment  of  the  negative  with  tincture  of 
iodine. — The  object  of  this  operation  is  to  con- 
vert the  metallic  silver  into  iodide  of  silver, 
which,  by  reason  of  its  greater  mass  and  its 
color,  is  less  permeable  to  the  light. 

The  plate  should  be  dried  and  washed  with 
alcohol,  before  pouring  the  tincture  of  iodine 
over  it.  When  the  desired  effect  has  been 
produced,  wash  well,  first  with  water,  then 
with  alcohol,  in  order  to  remove  the  excess  of 
iodine,  which  would  otherwise  act  on  the  sil- 
vered paper  during  the  printing. 


119 


3rd.  Strengthening  with  bichloride  of  mercury 
and  sulphur et  of  ammonium. — The  film,  before  it 
is  dry,  must  be  converted,  partially  or  entirely, 
into  the  double  chloride  of  mercury  and  silver 
by  the  application  of  a  solution  of  bichloride  of 
mercury,  then  washed  thoroughly,  and  treated 
with  a  solution  of  hydrosulphate  of  ammonia. 
The  effect  of  the  bichloride  of  mercury  is, 
firstly  to  blacken  the  image,  after  which  it 
commences  whitening  till  it  has  reached  a 
bluish  white  color.  During  its  action,  the 
operator  should  inspect  the  picture  from  time 
to  time,  by  holding  it  up  to  the  light.  When 
the  required  thickness  of  the  deposit  is  at- 
tained, the  action  of  the  mercury  salt  should 
be  stopped  by  washing.  Care  should  be  taken 
not  to  push  the  action  of  the  bichloride  too  far, 
as,  after  the  application  of  the  sulphuret  of 
ammonium,  the  opacity  would  be  such  that  it 
would  be  impossible  to  print  from  the  nega- 
tive. 

On  pouring  the  hydrosulphate  of  ammonia 
on  the  negative,  it  blackens  immediately,  the 
double  chloride  of  silver  and  mercury  being 
transformed  into  sulphuret  of  silver  and  sul- 
phuret of  mercury.  When  it  has  blackened 
all  through,  so  that  no  trace  of  the  former 
white  image  can  be  seen  on  the  side  of  the 
glass,  the  picture  should  be  washed; "it  has 
then  to  be  dried  and  varnished  in  the  ordinary 
way. 

The  solution  of  bichloride  of  mercury  should 


120 


not  be  too  strong,  in  order  to  prevent  the 
action  from  being  too  rapid.  One  part  of  the 
saturated  solution  with  two  parts  water  is  suf- 
ficient. The  saturated  solution  is  made  by  di- 
gesting an  excess  of  bichloride  of  mercury  with 
water. 

The  sulphuret  of  ammonium,  or  hydrosul- 
phate  of  ammonia,  is  sold  in  solution  by  drug- 
gists. It  should  be  diluted  with  ten  parts  of 
water.  As  it  has  a  strong  and  disagreeable 
smell  it  should  be  used  out  of  doors,  or  near  a 
window  where  there  is  a  powerful  draught.  The 
presence  of  this  gas  in  the  operating  rooms  is 
sufficient  to  cause  fogginess  of  the  pictures. 

The  double  chloride  of  silver  and  mercury, 
although  in  greater  mass  than  the  metallic 
silver  which  was  originally  on  the  plate, 
transmits  the  light,  so  that  the  blackening  or 
transformation  into  sulphuret  can  not  be  dis- 
pensed with. 

4th.  Strengthening  with  iodine,  pyrogallic 
acid  and  nitrate  of  silver. — The  image  is  con- 
verted into  iodide  of  silver  by  leaving  it  for 
five  or  ten  minutes  in  the  following  solution : 

Iodine,   1  grain. 

Iodide  of  potassium,   2  grains. 

Water,  ;   1  ounce. 

This  is  done  by  daylight.  The  plate  is 
then  well  washed,  taken  into  the  dark  room, 
and  redeveloped  with  pyrogallic  acid  and  sil- 
ver in  the  ordinary  way.  If  not  intense 
enough,  repeat  the  operation.    By  this  pro- 


121 


cess  any  amount  of  intensity  can  be  ob- 
tained from  weak  negatives.  It  is  thus  very 
valuable  in  making  copies  of  engraviiigs, 
pencil  sketches,  etc. 

5th.  Strengthening  with  bichloride  of  mercury 
and  bromide  of  potassium. — The  modus  operandi 
is  the  same  as  in  No.  3.  Instead  of  hydro- 
sulphate  of  ammonia,  a  two-grain  solution  of 
bromide  of  potassium  is  used.  The  color  of 
the  image  changes  to  a  slate  color  by  reflected, 
and  to  orange  brown  by  transmitted  light. 

Oth.  Strengthening  with  bichloride  of  mercury 
and  chloride  of  gold. — The  application  of  the  bi- 
chloride of  mercury  is  done  in  the  same  way 
as  described  in  'No.  3,  and  the  film  is  then 
covered  with  a  one-grain  solution  of  chloride 
of  gold,  which  changes  the  color  to  a  bluish 
black. 

7th,  Strengthening  with  bichloride  of  mercury 
or  chloride  of  gold. — The  application  of  either  of 
these  agents  darkens  the  color  of  the  film  and 
makes  it  more  impenetrable  to  the  chemical 
rays.  The  bichloride  should  not  be  left  on 
longer  than  is  necessary  to  blacken  the  film. 
Both  these  methods  are  very  useful  when  the 
negative  has  to  be  strengthened  but  little  to 
be  sufficiently  intense, 
n 


122 


CHAPTER  XXIII. 


Alcoholic  Collodion. 


The  proportions  of  ether  and  alcohol,  which 
will  dissolve  pyroxyline,  are  very  variable.  , 
Almost  any  mixture  of  the  two,  when  they  are 
in  the  most  concentrated  state,  will  do  it ;  but 
all  cannot  be  used  for  photographic  collodion. 
The  quantity  of  alcohol  which  can  be  used  for 
this  purpose  is,  however,  very  variable,  It  is 
much  larger  than  the  ordinary  proportion  re- 
commended when  the  cotton  is  of  the  variety  > 
which  gives  a  tough  and  contractile  film.  The 
advantages  claimed  for  collodion  containing 
an  excess  of  alcohol,  are  the  following : 

The  film  is  smooth,  structureless  and  very 
adherent. 

In  consequence  of  its  softness  and  porosity, 
the  film  is  in  a  favorable  condition  for  inten- 
sity and  sensitiveness. 

The  film  sets  slowly,  allowing  plenty  of  time 
in  the  hottest  weather  before  silvering. 

The  formation  of  the  collodio-iodide  of  sil- 
ver in  the  bath  proceeds  rapidly. 

The  collodion  keeps  longer  from  the  low 
temperature  at  which  the  pyroxyline  is  made, 
and  the  small  quantity  of  ether  which  enters 
into  its  composition. 


Ether,  7§0  S.  G 


60  grains  or  more 
1 2  ounces. 
,  4  ounces. 


Put  the  pyroxyline  in  four  ounces  of  the  al- 


123 


eohol,  shake  well,  add  the  ether,  and  when  all 
is  dissolved,  add  the  balance  of  the  alcohol. 
Iodize  according  to  the  directions  given  in  the 
chapter  on  Positive  Collodion. 

The  ether  and  alcohol  used  should  be  of  the 
greatest  strength.  If  none  sufficiently  strong 
can  be  procured,  the  best  that  can  be  found 
should  be  concentrated  by  means  of  quicklime, 
as  described  in  the  chapter  on  Collodion. 


CHAPE R  XXIV. 

Imperfections  in  Collodion  Photographs.* 

We  may  divide  the  imperfections  in  collo- 
dion photographs  into  three  sections : 

1st.  Imperfections  common  to  positives  and 
to  negatives. 

2d.  Imperfections  peculiar  to  positives. 

3d.  Imperfections  peculiar  to  negatives. 
SECTION  I. 
Imperfections  common  to  Positives  and  to  Negatives. 

These  are  fogging,  spots,  markings  of  all 
kinds,  etc. 

FOGGING. 

The  causes  which  produce  fogging  are  of 
two  kinds : 

1st.  Irregular  action  of  the  light. 
2d.  Impurity  of  the  chemicals. 

*  The  method  of  classification  of  this  chapter  has  been 
adopted  from  T.  Hardwich's  Photographic  Chemistry,  a 
work  which  we  consider  of  the  greatest  value,  and  the  study 
of  which  we  recommend  to  every  photographer 


124 


First — Irregular  Action  of  the  Light. 

A.  Over-exposure  of  the  plate. — This  is  often 
the  case  with  beginners,  who  do  not  know  the 
sensitiveness  of  the  collodion  process.  Over- 
exposure gives  only  the  appearance  of  foggi- 
ness,  when  three  or  four  times  longer  sitting 
is  given  than  what  is  required.  If  the  plate 
is  not  so  much  over  exposed,  the  image  is 
pale  and  flat  in  the  lights,  and  misty  in  the 
shadows. 

B.  Too  much  light  in  the  dark  room. — 1st, 
Owing  to  the  orange  pane  of  glass  through 
which  the  light  is  admitted  into  the  dark  room 
being  too  pale.  It  is  best  to  work  by  trans- 
mitted light,  through  either  two  thicknesses 
of  orange,  or  one  of  orange  and  one  of  red 
glass  combined.  2d,  By  the  light  of  the  can- 
dle or  lamp  being  too  strong.  When  the  film 
is  very  sensitive,  it  is  prudent  to  keep  the 
lamp  screened  by  an  orange  glass.  The  fog- 
giness  resulting  from  the  action  of  the  light 
may  sometimes  only  be  on  a  part  of  the  plate, 
as  is  the  case  when  the  light  acts  on  it  while 
it  is  in  the  silver  bath. 

C.  Light  entering  in  the  camera,  or  in  the 
tablet. 

D.  Direct  light  of  the  sun  falling  upon  the  lens. 
— This  produces  a  reflection  in  the  camera 
and  diminishes  the  vigor  of  the  image. 

E.  Diffused  light  of  the  sky  falling  upon  the 
lens.. — This  is  often  the  case  when  taking 
views.     Put  on  the  mouth  of  the  object 


125 


glass  a  tube  seven  or  eight  inches  long,  and 
blackened  inside.  In  this  way  there  will  be 
admitted  only  the  rays  proceeding  directly 
from  the  object  exposed,  and  the  diffusion  pro- 
duced by  the  lateral  rays  will  be  avoided. 
The  same  result  may  be  obtained  by  using  a 
diaphragm  with  a  small  aperture,  placed  two 
or  three  inches  distant  from  the  lens. 

Second — Impurity  of  the  Chemicals. 

A.  Use  of  fused  nitrate  of  silver  in  prepar- 
ing the  bath. — The  fogging  is  caused  by  an  ex- 
cess of  nitrate  of  silver.  The  remedy  is  the 
addition  of  a  few  drops  of  the  diluted  nitric 
acid.  Baths  prepared  according  to  the  form- 
ulas given  in  this  work  will  not  present  this 
inconvenience. 

B.  Use  of  Alkaline  Collodion. — Collodion  can 
be  made  alkaline  by  the  use  of  iodide  of  potas- 
sium which  contains  carbonate  of  potash,  as  is 
sometimes  the  case.  Alkaline  collodion  is  al- 
ways colorless ;  it  restores  the  blue  color  to 
reddened  litmus  paper.  The  remedy  is  to  put 
in  a  few  drops  of  hydrobromic  acid,  so  as  to 
give  it  a  pale  yellow  color. 

Collodion  prepared  with  iodide  or  bromide 
of  cadmium  remains  colorless  too  when  the 
ether,  alcohol,  and  gun  cotton  are  free  from 
acid.  This  is  not,  however,  a  mark  of  alka- 
linity, but  of  neutrality.  A  few  drops  of  hydro- 
bromic acid  can  only  improve  such  collodion 


126 


when  it  is  used  with  a  neutral  bath,  or  very 
slightly  acid  developing  solution. 

C.  Alkalinity  of  the  bath. — The  bath  becomes 
alkaline  when  an  excess  of  carbonate  of  soda, 
or  of  any  other  alkali,  is  added  to  it  for  the 
purpose  of  neutralizing  the  acid.  In  this 
case,  filter  and  add  nitric  acid  until  it  does 
not,  by  a  long  immersion,  restore  the  blue 
color  to  reddened  litmus  paper,  and  the  images 
obtained  are  clear. 

Rain  water  sometimes  contains  traces  of 
ammonia,  which  may  make  the  bath  alkaline. 
Hard  water,  containing  carbonate  of  limeh  will 
produce  the  same  effect. 

D.  Decomposition  of  the  bath  by  organic  mat- 
ter.— This  decomposition  is  accelerated  by  ex- 
posure to  light.  If  exposed  to  sunlight,  the 
solution  will  discolor,  and,  after  a  short  time, 
deposit  a  black  *  powder,  which  is  nothing  but 
reduced  silver.  It  is  then  again  ready  for 
use.  Before  being  exposed  to  the  light,  it  is 
best  to  neutralize  the  solution  by  the  addi- 
tion of  carbonate  of  soda.  (See  pp.  14  and  64.) 

E.  Introduction  of  developing  or  fixing  fluids 
into  the  solution, —prolonged  contact  with  rusty 
iron,  etc.— -If  the  neutralization  and  exposure  to 
sunlight  have  no  effect,  precipitate  the  silver 
with  carbonate  of  soda,  and  re-dissolve  in  nitric 
acid,  as  prescribed  on  page  85. 

F.  Vapors  of  ammonia,  hydrosidphate  of  am- 
monia, cyanide  of  potassium,  etc.  in  the  darkroom. 

G.  Re-dipping  the  plate  into  the  silver  solution 


127 


before  developing  it,  without  allowing  it  to  drain 
well 

H.  Imperfect  cleaning  of  the  glass. — In  this 
case  the  reduction  is  observed  between  the 
collodion  film  and  the  glass.  It  results  often 
from  the  cleaning  rags  not  being  dry,  or  soiled 
with  the  developing  or  fixing  solution. 

SPOTS. 

Spots  are  opaque  or  transparent  by  trans- 
mitted light,  white  or  black  by  reflected  light. 

Opaque  Spots  are  Produced  : 

A.  By  collodion  having  small  particles  in  sus- 
pension.— Comet-shaped  specks  are  produced 
by  this  cause.  Also  little  circular  specks, 
which,  after  washing,  leave  holes. 

B.  By  not  cleaning  the  month  of  the  bottle,  so 
that  fragments  of  dried  collodion  are  floated  on 
to  the  plate. 

C.  By  dust  in  the  tablet  or  in  the  camera,  or 
by  moving  the  slide  in  and  out  of  the  tablet  with 
violence,  so  that  small  particles  of  organic  matter 
or  drippings  of  the  plate  are  spattered  on  the  film. 

D.  By  the  drippings  of  the  plate  not  coming  in 
contact  with  the  wood  frf  the  tablet  or  with  the 
glue  with  which  the  glass  corners  are  sealed 
in. — The  plate  should  be  well  drained,  and 
a  piece  of  blotting  paper  put  on  the  back,  so 
that  all  the  drippings  be  absorbed  by  it.  The 
corners  should  also  be  dried  after  each  oper- 
ation,   Tablets  with  solid  glass  corners  are 


128 


preferable  to  any  other  kind.  Those  with 
pieces  of  glass  glued  in  the  corners  give  great 
trouble  when  they  are  new.  The  best  course 
in  this  case  is  to  take  the  pieces  of  glass  out 
and  seal  them  in  again  with  beeswax.  This 
is  easily  done  by  putting  a  small  piece  of  wax 
in  the  corner,  warming  the  piece  of  glass  on 
the  point  of  a  knife,  and  pressing  it  down  on 
the  wax.  The  spots  produced  by  the  tab- 
let are  mostly  on  the  lower  corners,  above  the 
head,  in  a  portrait. 

Transparent  Spots  are  Produced, 

A.  By  the  silver  solution  being  over-saturated 
tvith  iodo-nitrate  of  silver. — The  solution  be- 
coming weakened  by  use,  the  iodo-nitrate  will 
take  a  crystalline  form  and  deposit  on  the 
film,  and  will  afterwards  be  washed  off,  or 
dissolved  by  the  fixing  solution,  leaving  little 
transparent  spots  like  pin-holes.  The  remedy 
has  been  given  on  page  83. 

B.  By  small  particles  of  iodide  of  potassium, 
or  of  bromide  of  potassium,  or  ammonium  in  the 
collodion. — Allow  the  collodion  to  settle,  and 
add  some  collodion  iodized  with  the  cadmium 
salts. 

C.  Small  particles  in  suspension  in  the  develop- 
ing  solution. — The  developing  solutions  should 
always  be  carefully  filtered  before  being  used. 

D.  By  a  deposit  formed  on  the  side  of  the  bath, 
a  deposit  which  is  the  result  of  the  decomposi- 
tion of  the  silver  solution  by  organic  matter. 


129 


The  remedy  is  to  clean  the  bath  well  out  and 
filter  the  solution. 

E.  By  irregular  action  of  the  developing  fluid. 
— The  silver  solution  which  is  on  the  plate 
may  be  washed  off  in  some  places  by  the  devel- 
oper not  being  properly  poured  on.  In  this 
case  the  reduction  of  silver  will  not  take  place 
on  that  part  of  the  plate,  and  a  greenish  trans- 
parent spot  will  be  produced. 

Markings  of  Various  Kinds. 

A.  A  reticulated  appearance  of  the  film,  affect- 
ing  the  form  of  a  net-work  or  honey-comb. — 
The  collodion  is  glutinous,  or  contains  too 
much  water.  In  the  first  case  ammonia  will 
improve  it,  as  will  also  the  action  of  alkaline 
iodides.  In  the  second  case  it  is  worthless,  or 
can  only  be  used  to  mix  with  collodion  made 
with  very  concentrated  ether  and  alcohol. 

B.  The  film  is  cracked  all  over  when  dry. — 
The  collodion  is  rotten  from  the  cotton  having 
been  decomposed  in  the  nitro-sulphuric  acid, 
or  from  the  action  of  alkalies  or  alkaline 
iodides  or  bromides.  Such  collodion  can  be 
mixed  with  advantage  with  a  sample  which  is 
glutinous,  their  respective  peculiarities  des- 
troying each  other.  Mixed  with  a  variable 
quantity  of  good  negative  collodion,  it  is  just 
the  thing  for  the  dry  collodion  processes. 
Such  collodion  may  be  improved  by  an  addi- 
tion of  good  cotton. 

C.  Straight  lines  traversing  the  film  horizon- 


130 


tally. — These  are  caused  by  checks  having 
been  made  during  the  immersion  of  the  plate 
into  the  bath. 

D.  Streaks  or  lines  in  the  direction  the  "plate 
has  been  dipped. — These  streaks  or  lines  are 
in  the  film  or  on  the  surface.  In  the  first 
case,  they  are  the  result  of  the  action  of 
water  on  the  pyroxyline,  and  denote  one  of  the 
following  states ;  The  silver  solution  is  too 
weak  ;  the  silver  solution  is  at  too  low  a  tem- 
perature ;  the  collodion  is  not  well  set,  or 
it  contains  too  much  alcohol.  If  the  lines  or 
streaks  are  on  the  surface  so  that  after  the 
plate  is  dry  they  can  be  dusted  off  with  a 
camel-hair  brush,  they  are  the  result  of  the  use 
of  a  silver  solution  which  has  a  tendency  to 
fogging. 

E.  Oily  spots  of9  lines.- — These  occur  when 
the  plate  is  taken  out  of  the  silver  solution 
before  the  alcohol  has  been  dissolved  into  the 
bath.  They  are  also  caused  in  the  develop- 
ment, when  the  developing  solution  does  not 
unite  readily  with  the  film.  The  remedy  in 
the  last  case  is  an  addition  of  alcohol  to  the 
developing  solution.  When  the  solution  is 
poured  off  before  the  action  ceases,  oily  lines 
are  formed  on  the  end  of  the  plate  which  is  held 
uppermost. 

F.  Curved  lines  of  irregidar  development. — 
These  result,  1st,  from  over  exposure  of  the 
plate.  2d,  From  excess  of  protosulphate  of 
iron  or  pyrogallic  acid.    3d,  From  unskillfully 


*  131 


covering  the  plate  with  the  developing  fluid. 
4th,  From  using  too  small  a  quantity  of  devel- 
oping fluid. 

G.  Uneven  film  of  collodio-iodide  of  silver. — 
This  is  produced,  1st,  When  the  collodion 
contains  too  much  ether,  so  that  it  dries  too 
soon.  2d,  When  the  collodion  is  made  with 
a  bad  sample  of  cotton.  3d,  When  it  is  too 
thick. 

In  the  first  case,  add  strong  alcohol,  until 
the  collodion  contains  equal  parts  of  alcohol 
and  ether,  and  dissolve  into  it  more  cotton. 
In  the  second,  add  a  large  quantity  of  alco- 
hol, so  as  to  have  it  in  excess.  In  the  third 
case,  dilute  with  equal  parts  of  ether  and  alco- 
hol, previously  mixed  together,  and  iodized 
if  necessary. 

H.  Irregular  stains  of  metallic  silver  on  the 
surface  of  the  film,  which  can  be  dusted  off  and 
leave  a  transparent  mark. — These  marks  are 
produced  by  a  scum  floating  on  the  surface  of 
th,e  solution,  and  sticking  on  the  plate  when 
it  is  dipped.  Add  new  solution  so  as  to  cause 
this  scum  to  flow  over  in  the  small  part  of  the 
overflowing  bath,  or  remove  it  with  a  piece 
of  blotting  paper. 

I.  Marks  like  fern  leaves  in  the  film. — . 
Are  caused  by  an  inferior  sample  of  cotton 
being  used,  made  with  weak  afcids  and  at  a 
high  temperature. 

J.  Peeling  up  of  the  collodion  film  after  drying. 
— This  results  from  a  peculiarity  of  the  pyrox- 


132 


yline.  It  happens  most  frequently  on  glasses 
which  have  not  been  well  cleaned.  To  pre- 
vent it,  coat  the  plate  with  gum  arabic  before 
drying,  and  if  the  film  commences  peeling, 
varnish  the  edges  with  benzine  varnish  by 
means  of  a  small  soft  brush.  The  remedy  is 
to  increase  the  quantity  of  alcohol  in  the  collo- 
dion, so  as  to  make  it  softer  and  less  contractile. 

SECTION  II. 
Imperfections  Peculiar  to  Positives. 

A.  The  image  shoivs  well  in  the  high  lights, 
but  the  shadows  are  dark  and  heavy. — This 
results  mainly  !Tfrom  excess  of  intensity,  in 
which  case  add  bromide  to  the  collodion 
till  the  contrast  is  sufficiently  reduced.  If 
such  an  appearance  exists  without  the  high 
lights  being  intense  by  transmitted  light,  it  is 
the  result  either  of  under  exposure,  or  excess 
of  nitric  acid  in  the  bath  or  in  the  developer. 

B.  The  shadows  are  good,  but  the  lights  are 
over  done. — The  collodion  gives  too  intense 
images.  Thin  with  ether  and  alcohol,  or  add 
more  bromide. 

C.  The  image  is  flat,  without  sufficient  contrast 
between  the  lights  and  shadows. — This  results,  1st, 
From  over  exposure.  2d,  From  the  use  of  col- 
lodion which  is  either  too  thin  or  contains  too 
much  bromide. 

D.  The  shadows  are  grey  and  misty. — The 
bath  has  a  tendency  to  fogginess,  or  the  image 
has  been  over  developed. 


133 


E.  The  whites  are  grey  and  metallic,  or  yellow 
and  dead. — Good  whites  are  very  much  the 
result  of  a  favorable  molecular  condition  of 
the  film.  A  rather  short  and  porous  film 
gives  the  best  whites.  Tough  and  hard  films 
give  generally  grey  and  metallic  whites  in 
connection  with  much  acid  in  the  bath  or  in 
the  developer,  and  yellow  and  dead  whites 
when  acid  has  been  sparingly  used. 

F.  The  shadows  are  covered  with  little  specks, 
similar  to  those  produced  on  daguerreotypes,  by 
leaving  them  too  long  on  the  mercury. — The  bath 
contains  organic  matter.  It  should  thus  be 
exposed  to  sunlight  and  filtered.  When  there 
is  no  time  for  doing  this,  give  an  exposure  a 
little  longer  and  develop  a  little  less.  This 
effect  is  also  often  produced  in  re-developing. 

SECTION  III. 
Imperfections  Peculiar  to  Negatives. 

A.  Want  of  intensity. — 1st,  From  the  collo- 
dion being  made  with  unsuitable  cotton.  2d, 
From  the  collodion  being  too  thin.  3d,  From 
excess  of  bromide  in  the  collodion.  As  a 
remedy,  add  to  it  as  much  good  cotton  as  it 
will  bear.  If  this  is  not  followed  by  a  good 
result,  let  it  become  old.  The  action  of  the 
alkaline  iodides  or  bromides  it  contains  will 
soon  change  the  condition  of  the  film  and 
cause  it  to  produce  intense  images.  The  addi- 
tion of  a  quantity  of  old  and  red  collodion 
may  be4  resorted  to.    4th,  Want  of  intensity 


134 


from  acidity  or  impurity  of  the  silver  solution. 
Remedy  :  Neutralize  and  expose  to  the  light. 
5th,  From  the  plate  being  kept  too  long  be- 
tween silvering  and  developing.  6th,  From 
want  of  intensity  in  the  light. 

B.  Excess  of  intensity  in  the  high  lights  and 
want  of  definition  in  the  shadows. — 1st,  The 
collodion  possesses  the  intense  qualities  to 
a  too  great  extent.  Remedy:  Addition  of 
bromide  or  of  positive  collodion.  2d,  The 
light  is  too  contrasted. 

C.  Intensity  all  over  and  absence  of  contrast 
between  lights  and  shades. — The  plate  has  been 
over-exposed. 

D.  The  high  lights  are  well  marked  without 
being  very  intense,  the  shadows  are  deficient  in  de- 
tails, and  the  image  looks  quite  well  by  reflected 
light. — The  plate  has  been  under-exposed. 

The  imperfections  mentioned  above  are 
common  to  negatives  developed  either  by 
pyrogallic  acid  or  by  the  iron  salt,  without 
being  pushed  or  re-developed. 


CHAPTER  XXV. 

Positives  on  Paper. 

Two  methods  are  adopted  to  produce  posi- 
tives on  paper.  1st,  the  ordinary  positive 
process,  in  which  the  silver  is  reduced  directly 
by  the  light ;  and  2d,  the  process  called  nega- 


135 


tive,  because  it  is  used  also  to  produce  nega- 
tives on  paper,  in  which  the  silver  is  reduced 
by  the  subsequent  action  of  light  and  of  a  de- 
veloper. 

In  the  ordinary  positive  process,  the  paper 
is  immersed  into  a  solution  of  some  chloride, 
then  treated  with  a  solution  of  nitrate  of  silver, 
so  that  by  double  decomposition  chloride  of 
silver  is  produced.  It  is  now  dried  and  ex- 
posed under  the  negative  to  the  light,  until  a 
sufficient  reduction  has  taken  place,  after  which 
the  unreduced  chloride  of  silver  is  dissolved 
by  a  solution  of  hyposulphite  of  soda. 

In  the  process  called  negative,  the  paper  is 
floated  on  a  solution  of  iodide,  or  bromide,  or 
chloride,  and  then  on  a  solution  of  nitrate  of 
silver.  Having  dried  it  and  placed  it  under 
the  negative,  expose  it  to  the  light,  and  develop 
the  image  by  means  of  gallic  acid.  The  un- 
reduced iodide  of  silver  is  finally  dissolved  by 
hyposulphite  of  soda. 

Selection  of  the  Paper. — The  ordinary  paper, 
containing  substances  which  are  injurious  -in 
the  photographic  operation,  and  being  of  an 
unequal  texture,  is  unfit  for  use.  Several 
papers  are  manufactured  purposely.  The 
Saxe  of  German  and  the  Rive  of  French 
manufacture,  are  best  known.  The  former 
is  much  the  best  as  to  texture,  and  printing 
and  strength,  but  the  Rive  is  preferred  by 
many,  principally  when  albumenized,  on  ac- 
count of  the  rich  tone  of  the  prints. 


136 


A  good  photographic  paper  is  smooth,  uni- 
form in  texture,  of  an  equal  thickness  in  every 
part,  and  free  from  spots.  The  smoothest  side 
should  be  used  to  receive  the  impression,  and 
the  opposite  side  marked  with  a  pencil.  The 
wrong  side  of  the  paper  can  be  easily  detected 
by  the  wire  markings,  mainly  after  it  has  been 
salted.  These  can  best  be  seen  by  holding 
the  sheet  in  such  a  way  that  the  lig:ht  strikes 
it  at  an  angle. 


CHAPTER  XXYI. 

Direct  Positive  Process. 

The  points  to  be  considered  in  the  prepara- 
tion of  the  sensitive  paper  are :  Sensitiveness, 
intensity,  contrast  or  vigor,  delineation,  and 
+one  or  color. 

Sensitiveness. — The  sensitiveness  of  the  pa- 
per depends : 

1st,  On  the  quantity  of  chloride  of  silver 
on  the  paper.  The  quantity  of  chloride  of 
silver  is  determined  by  the  quantity  and  species 
of  alkaline  chloride  used  in  the  salting,  and  by 
the  process  of  salting.  The  sensitiveness  of 
highly  salted  paper  is  greater  than  of  one  in 
which  but  a  small  quantity  of  salt  has  been 
used,  provided,  however,  the  quantity  of  nitrate 
of  silver  be  in  proportion.  The  sensitiveness 
however  does  not  increase  after  a  certain  point 


137 


is  reached,  and  this  point  depends  on  the 
thickness  and  sizing  of  the  paper,  or  on  the 
process  used  in  salting.  Thick  paper  and 
paper  sized  with  gelatine  will  retain  a  larger 
proportion  of  salt  than  that  which  is  thin  or 
sized  wTith  starch.  Immersing  salts  more 
than  floating,  and  floating  more  than  brushing. 
The  alkaline  chloride  used  is  also  a  point  of 
great  importance,  the  chloride  of  ammonium 
containing  more  chlorine  than  the  chloride 
of  sodium  (common  salt),  and  this  more  than 
the  chloride  of  barium. 

5  grains  chloride  of  ammonium  yield  the  same  quantity 

of  chloride  of  silver  as..  5^  grains  chloride  of  sodium. 

**  H   11  grains  chloride  of  barium. 

2d,  On  the  quantity  of  nitrate  of  silver  on 
the  surface,  and  on  the  greater  or  less  facility 
with  which  this  nitrate  of  silver  is  reduced. 
— When  a  salted  paper  is  floated  on  a  solu- 
tion of  nitrate  of  silver,  the  chloride  which  is 
in  the  paper  and  the  nitrate  of  silver  will  de- 
compose each  other,  forming  chloride  of  silver, 
which,  with  the  nitrate  of  silver  retained  by 
the  paper,  forms  the  sensitive  compound  on 
which  the  image  is  produced. ».  If  the  bath  is 
strong,  the  quantity  of  free  nitrate  of  silver 
will  also  be  larger,  'and  the  paper  will  be  sen- 
sitive in  proportion.  In  case  it  is  brushed  on, 
the  quantity  of  solution  which  is  used  will  be 
much  reduced  in  strength,  and  the  paper  wil$ 
be  less  sensitive  than  if  it  is  floated.  It  wilj 
thus  be  necessary  in  the  latter  case  to  '  use  % 


138 


stronger  solution,  if  the  same  result  is  to  be 
attained.  Paper  sensitized  with  an  acid  silver 
solution  is  less  sensitive  than  the  one  sensi- 
tized with  a  neutral  one.  The  one  prepared 
with  the  solution  of  oxide  of  silver  in  ammo- 
nia (ammonia  nitrate  of  silver)  is  the  most 
sensitive  of  all,  from  the  greater  facility  with 
which  this  compound  is  reduced. 

3d,  On  the  use  of  organic  matters.  Those 
generally  used  are  the  albumen,  gelatine,  and 
iceland  moss.  All  increase  the  sensitiveness 
of  the  paper,  but  the  albumen  a  great  deal 
more  than  the  others. 

Intensity,  Contrast,  Yigor. 

The  intensity  of  the  print  depends  in 
some  measure  on  the  disproportion  between 
the  amount  of  salt  and  the  amount  of  silver. 
Salt  determines  sensitiveness,  and  silver  in- 
tensity. Nothing  is  gained  in  intensity,  how- 
ever, in  using  an  amount  of  silver  unusually 
large,  and  an  amount  of  salt  unusually  small. 
The  ammonia  nitrate  gives,  in  proportion, 
much  more  intensity  than  the  plain  nitrate 
of  silver.  With  a  weak  negative,  it  should 
thus  be  used  in  preference.  Albumen  paper 
gives  more  intensity  than  gelatine  paper,  and 
this  one  more  than  the  plain.  The  presence 
on  the  paper  of  easily  reduced  salts  of  silver, 
such  as  the  acetate,  the  citrate,  etc.,  also  in- 
crease the  intensity. 


339 


Delineation  or  Shakpness. 

Independently  of  the  texture  of  the  paper, 
the  sharpness  of  the  print  depends  on  the  use 
of  albumen,  gelatine,  gum  arabie,  iceland 
moss,  etc.  These  substances  act  in  keeping 
the  image  on  the  surface  of  the  paper,  and  in 
filling  up  its  pores.  Albumen  paper  gives 
the  sharpest  prints  of  all.  Papers  prepared 
with  the  other  substances  mentioned,  although 
giving  less  definition  than  the  albumen,  are  a 
great  improvement  on  the  plain. 

Tone  or  Color. 

The  color  of  a  print,  both  before  and  after 
toning,  depends  in  a  great  measure  on  the 
sizing  of  the  paper.  The  German  or  Saxe 
papers  print  black  or  bluish  black ;  the  Rive 
or  French  papers  print  reddish.  The  charac- 
ter of  these  papers  remains  after  they  are 
albumenizecl. 

Weak  silver  solutions  give  red  tones  also, 
more  especially  so  when  used  in  connection 
with  weak  salting.  Paper  prepared  with  am- 
monia-nitrate of  silver,  or  prepared  with  plain 
silver,  and  fumed  with  ammonia,  prints 
blacker  than  plain  silvered  paper. 

Whatever  be  the  color  of  the  print  on 
being  removed  from  the  printing  frame,  it 
can  be  brought  to  a  more  or  less  pure  black 
in  the  toning  bath.  Saxe  paper  as  a  general 
thing,  gives  a  purer  black  than  the  Rive  paper, 


140 


which  gives  prints  of  a  warmer  tone.  These 
remarks  hold  good  whether  the  paper  be 
albumenized  or  not ;  but  in  the  former  case, 
the  toning  is  more  difficult  and  takes  longer. 


CHAPTER  XXVII. 

Preparation  of  the  Sensitive  Paper. 

In  the  former  editions  of  this  work  we  gave 
three  different  direct  printing  processes  :  1st, 
The  process  on  plain  salted  paper,  floated  on 
a  plain  solution  of  nitrate  of  silver.  2d,  The 
ammonia-nitrate  process,  or  process  on  plain 
paper,  brushed  over  with  ammonia-nitrate  of 
silver.  3d,  The  process  on  albumenized 
paper.  Since  then  certain  modifications  have 
been  introduced  into  the  printing  processes, 
which  render  obsolete  a  good  deal  of  what  we 
said.  We  have  thus  entirely  re-written  all 
that  appertains  to  the  printing  processes,  and 
noticed  or  mentioned  every  improvement 
Avhich  has  been  made  in  this  important  branch 
of  photography. 

Printing  being  done  generally  either  on 
plain  or  gelatinized  paper,  or  on  albumenized 
paper,  we  will  divide  our  description  of  the 
sensitizing  into  two  parts  :  1st,  Preparation 
of  the  sensitive  plain  paper  ;  2d,  Preparation 
of  the  sensitive  albumen  paper. 

Preparation  of  the  sensitive  plain  paper. — 


141 


Either  the  Saxe  or  the  Rive  paper,  can  be 
used  in  this  process ;  the  latter  giving,  under 
the  same  conditions,  a  warmer  tint  than  the 
former. 

The  first  preparation  is  the  salting,  which 
can  be  done  either  with  chloride  of  sodium, 
of  ammonium,  or  of  barium  ;  but  the  chloride 
of  ammonium,  being  easier  obtained  in  a  pure 
state,  is  generally  preferred.  As  regards  sen- 
sitiveness, color  and  intensity,  these  three 
salts  give  the  same  results,  when  used  in 
equivalent  proportions.*  The  salting  solution 
is  made  according  to  the  following  formula : 


Water,  

Chloride  of  ammonium, 
White  gelatine,  


32  ounces. 
.80ft  grains. 
.40  grains. 


The  gelatine  is  used  in  order  to  introduce 
into  the  paper  a  larger  quantity  of  the  kind 
of  organic  matter,  which  easily  reduces  the 
silver  salts.  The  effect  of  its  introduction 
is  more  boldness  and  vigor  in  the  print. 

The  gelatine  is  put  into  a  part  of  the  water 
for  about  an  hour,  when  it  will  have  become 
soft  and  swollen.  A  slight  application  of 
heat  will  then  suffice  to  dissolve  it,  after  which 
the  chloride  of  ammonium  and  the  rest  of  the 
water  are  added,  and  the  solution  is  filtered. 

A  larger  quantity  of  chloride  of  ammonium 
may  be  used,  and  will  increase  the  sensitive- 

*  We  are  aware  that  a  contrary  view  is  entertained  by- 
high  authority,  but  we  came  to  this  conclusion  after  some 
careful  experiments  undertaken  to  test  this  matter. 


142 


ness  of  the  silvered  paper;  but  unless  the  in- 
tensity of  the  negative  be  increased  in  pro- 
portion to  the  amount  of  chloride,  the  print 
produced  will  be  grey  and  cold. 

For  solar  camera  dry  printing,  where  a 
greater  sensitiveness  is  required  than  for  con- 
tact printing,  as  much  as  ten  grains  to  the 
ounce  may  be  used  with  advantage ;  but  no 
good  effect  can  be  expected  by  the  use  of  fif- 
teen and  twenty  per  cent  salt  solutions,  (cor- 
responding to  seventy  and  ninety  grains  to 
the  ounce,)  such  as  were  used  a  few.  years 
back,  principally  in  Continental  Europe. 

Some  printers  add  to  this  salting  solution 
168  grains  of  citric  acid,  and  200  grains  bicar- 
bonate of  soda.  These  two  substances,  acting 
on  each  other,  form  citrate  of  soda,  which,  on 
floating  the  paper  on  the  silver  solution,  is 
transformed  into  citrate  of  silver.  The  effect 
of  this  citrate  of  silver  is  to  give  a  warmer 
tone  to  the  print.  This  addition  is  not  to  be 
recommended  when  the  Rive  paper  is  used. 

The  paper  is  immersed  in  this  salting  solu- 
tion, and  the  air-bubbles  removed  with  a  soft 
brush,  after  which  it  is  hung  up  to  dry.  It 
is  advisable  not  to  leave  it  in  'longer  than  is 
necessary,  in  order  to  avoid  the  picture  sink- 
ing into  the  texture  of  the  paper. 

The  plain  paper  can  be  sensitized  in  two 
different  ways  :  1st,  By  brushing  over  it  a 
solution  of  ammonia-nitrate  of  silver ;  2d,  by 
floating  the  paper  on,  or  brushing  over  it,  a 


143 


solution  of  plain  nitrate  of  silver,  and  when 
dry,  exposing  it  to  the  fumes  of  ammonia. 
Both  processes  give  about  the  same  result. 

We  will  here  describe  the  first  process  of 
silvering,  and  refer  the  reader  for  the  second 
process  to  the  heading,  Preparation  of  the 
sensitive  albumen  paper. 

The  ammonia-nitrate  of  silver  solution  is 
made  in  the  following  way :  Dissolve  one 
ounce  of  nitrate  of  silver  in  four  ounces  of 
water ;  of  this,  reserve  for  future  use  about  h 
ounce  fluid,  and  to  the  other  3^  ounces  add 
ammonia,  a  small  quantity  at  a  time,  stirring 
with  a  glass  rod  after  each  addition.  A  brown 
precipitate  of  oxide  of  silver  will  form,  which, 
on  the  addition  of  a  sufficient  quantity  of  am- 
monia, will  be  re-dissolved.  When  this  point 
is  attained,  the  liquid  becomes  clear  again, 
(unless  the  nitrate  of  silver  contained  certain 
impurities,)  but  it  will  contain  an  excess  of 
ammonia,  which  would  cause  the  prepared 
paper  to  become  brown  very  quick.  To  avoid 
this,  add  the  half  ounce  nitrate  of  silver  solu- 
tion which  had  been  set  apart,  and  filter  the 
liquid  to  separate  the  precipitate  which  is 
thrown  down ;  finally  add  water  until  you  have 
a  bulk  of  eight  ounces,  and  put  in  three  or  four 
drops  of  nitric  acid.  In  this  way  a  solution 
of  nitrate  of  silver,  of  the  strength  of  sixty 
grains  to  the  ounce,  is  obtained. 

The  ammonia-nitrate  of  silver  solution 
should  be  applied  on  the  paper  by  means  of 


144 


a  brush  or  a  tuft  of  cotton,  and  not  by  floating 
it  on  the  solution.  The  reason  for  this  is, 
that  by  the  reaction  of  the  chloride  of  sodium 
on  the  ammonia  nitrate  of  silver,  ammonia  is 
set  free  and  dissolves  in  the  solution,  which 
in  this  way  takes  an  excess  from  the  first 
paper  which  is  floated.  This  excess  of  am- 
monia dissolves  the  chloride  of  silver  which 
is  formed,  and  also  causes  the  paper  to  become 
brown  very  shortly  after  it  is  sensitized,  and 
sometimes  evefti  while  it  is  on  the  solution. 

The  most  convenient  way  to  apply  the  am- 
monia-nitrate of  silver  solution  is  by  the  use 
of  a  cotton  brush.  To  make  a  cotton  brush, 
take  a  tuft  of  cotton  wool,  about  four  inches 
long  and  half  as  wide,  tie  a  piece  of  twine  in 
the  middle,  and  by  means  of  this  draw  the 
cotton  into  a  glass  tube,  then  cut  off  what  is 
superfluous. 

To  silver  the  paper,  pin  it  on  a  flat  board 
which  you  have  covered  with  a  sheet  of  blot- 
ting paper,  pour  on  it  a  small  quantity  of  the 
silver  solution,  and  brush  firstly  lengthways, 
and  then  across,  taking  care  to  distribute  it 
equally  all  over,  after  which  you  hang  it  up  to 
dry.  'Be  careful  to  use  nitrate  solution  enough 
to  transform  all  the  chloride  of  ammonium 
into  the  chloride  of  silver.  This  will  take 
about  four  drachms  for  a  sheet  of  photographic 
paper.  For  the  first  sheet  you  silver  you  will 
have  to  take  one  drachm  more,  that  much 
being  absorbed  by  the  brush.    The  drippings 


145 


should  not  be  returned  to  the  stock  bottle,  as 
this  would  bring  an  excess  of  ammonia  into 
the  solution  it  contains.  The  brush  can  be 
used  several*  times,  if  kept  out  of  the  dust 

Ammonia-nitrate  paper  should  only  be  pre- 
pared on  the  same  day  it  has  to  be  used,  for 
it  soon  becomes  brown  and  loses  sensitiveness. 

Preparation  of  the  Sensitive  Albumen  Paper. 

Albumenized  photographic  paper  is  kept  on 
hand  by  stock  dealers.  Both  Saxe  and  Rive 
papers  are  used  for  the  purpose.  The  former 
is  superior  in  texture  to  the  .  latter,  and  is  also 
more  free  from  spots ;  but  the  Rive  gives 
prints  of  a  warmer  and  more  pleasing  tone. 
This  is  on  account  of  the  substances  which 
are  used  for  sizing  it.  The  Saxe  paper  is 
almost  the  only  one  used  in  this  country. 
Three  kinds  of  Saxe  are  manufactured  :  the 
negative,  the  half  thick,  and  the  thick.  The 
negative  and  half  thick  are  .ghostly  used  for 
albumenizing. 

The  albumen  for  albumenizing  paper  is 
prepared  in  the  following  manner:  Take 
the  whites  of  fresh  eggs  well  separated  from 
the  yolk,  and  beat  with  a  wooden  fork  or  a 
bundle  of  quills,  or  by  means  of  a  patent  egg- 
beater,  until  the  whole  has  become  a  perfect 
froth.  This  point  is  reached  when  the  vessel 
in  which  the  albumen  is  beaten,  can  be  turned 
upside  down  without  any  liquid  running  out. 
Then  allow  the  froth  to  subside,  which  will 

13 


146 


take  several  hours  ;  to  each  ounce  of  liquid 
add  from  five  to  ten  grains  of  chloride  of  am- 
monium, Filter  through  a  sponge  or  through 
a  tuft  of  cotton,  or  let  settle,  and  pour  the 
clear  parts  into  a  glass  or  porcelain  tray. 

The  floating  of  the  paper  on  the  albumen 
requires  some  skilly  and  this  is  only  acquired 
by  practice.  The  most  convenient  and  easiest 
way  is,  to  take*  the  sheet  by  its  upper  corners, 
lay  it  on  the  surface  of  the  albumen,  with  its 
upper  end  near  the  lower  end  of  the  tray, 
and  then  let  it  come  down  slowly,  gradually 
pushing  the  sheet  before  you.  The  paper  is 
left  on  the  albumen  for  one  or  two  minutes, 
after  which  it  is  hung  up  to  dry,  suspending 
either  with  patent  clips,  or  slinging  it  over  a 
cord. 

The  albumen  should  never  be  used  when  it 
is  decomposed  and  emits  a  strong  smell.  Al- 
bumen paper  should  also  be  kept  in  a  dry 
place,  in  order  to  keep  the  albumen  on  the 
surface  from  decomposing. 

Mr.  Thomas  Sutton  recommends  passing 
the  paper  through  a  solution  of  india  rubber 
in  benzine,  before  albumenizing  it.  In  this 
way  the  albumen  is  kept  from  sinking  in 
the  paper,  and  the  sizing,  it  is  claimed,  does 
not  interfere,  to  the  same  extent,  with  the 
color  of  the  print.  The  process  is  patented 
in  Great  Britain. 

The  fuming  of  the  paper  with  ammonia 
after  it  has  been  sensitized,  dispenses  with  the 


147 


use  of  a  strong  silver  solution.  A  forty  grain 
solution  used  in  connection  with  fuming, 
seems  to  produce  about  the  same  effect  as  the 
use  of  an  eighty  grain  solution  used  without. 
The  fuming  process  is  now  generally  adopted. 

The  question  of  advantage  in  the  use  of 
strong  or  weak  baths,  is  one  which  has  lately 
occupied  much  of  the  attention  of  photo- 
graphic writers.  In  our  opinion,  the  strength 
of  the  silver  solution  should  depend  on  the 
strength  of  the  salting,  and  on  the  intensity 
of  the  negative  ;  or,  to  be  more  explicit,  on  the 
contrast  existing  between  the  high  lights  and 
the  shadows. 

Weak  salting  requires  only  a  weak  silver 
solution,  and  all  beyond  a  certain  strength  is 
superfluous.  Strong  salting,  on  the  contrary, 
requires  strong  silvering.  A  weak  negative 
requires  strong  silvering  ;  an  intense  one 
will  produce  the  best  results  with  a  weak  sil- 
ver solution. 

As  a  rule,  the  strength  of  a  silver  solution 
for  a  given  negative  or  a  class  of  negatives, 
should  be  such,  that  in  printing,  the  shadows 
are  bronzed  at  the  time  the  lighter  parts  are 
sufficiently  brought  out.  If  this  effect  is  not 
produced,  either  a  stronger  silver  solution 
should  be  used,  or  the  paper  should  be  fumed, 
or  both  expedients  should  be  used  in  connec- 
tion, if  one  does*  not  give  the  expected  result. 
If,  on  the  contrary,  the  dark  parts  get  bronzed 
long  before  the  lights  are  sufficiently  printed, 


148 


producing  a  print  devoid  of  transparency  in 
the  shadows,  the  solution  should  be  weakened. 

The  plain  silver  solution  generally  used,  is 
prepared  according  to  the  following  formula : 


The  alcohol  is  added  to  keep  the  solution 
from  becoming  discolored  by  use.  The  way 
an  addition  of  alcohol  produces  this  effect  is 
explained  in  the  following  manner  :  Albumen 
forms,  with  the  silver  salt,  an  insoluble  com- 
pound ;  but  before  the  compound  has  time  to 
be  completely  formed,  a  small  portion  of  the 
albumen  is  dissolved  into  the  bath  and  dis- 
colors it  in  the  same  way  as  any  other  kind 
of  organic  matter  would.  But,  by  adding 
alcohol  to  the  bath,  its  solvent  powrer  is  de- 
creased, and  with  it  also  its  tendency  to  dis- 
color. 

The  strength  of  the  solution  given  above 
should  be  kept  up  by  the  addition  of  another 
one  made  as  follows : 


It  can  also  be  tested  from  time  to  time,  by 
means  of  the  Silver  Indicator*  and  the  neces- 
sary amount  of  nitrate  of  silver  added  to  it. 

To  sensitize  a  paper  by  floating,  take  it  by 

*  Sold  by  Scovill  Manufacturing  Company. 


Nitrate  of  silver, 
Distilled  water,. 

Alcohol,  

Nitric  acid,. . . . 


4J^  ounces  fluid, 
lj/o  ounces  fluid. 
2  drops. 


ounce. 


titrate  of  silver, 

Water,  

Alcohol,  - ...  ... 

Nitric  acid,  


,  1  ounce. 
3  ounces  fluid. 
,  1  ounce  fluid. 
.2  drops. 


149 


two  opposite  corners,  and  having  bent  it  into 
a  curved  form,  lay  it  on  a  silver  solution,  the 
middle  part  touching  first,  and  lowering  grad- 
ually down,  taking  care  to  avoid  air-bubbles. 
If  these  occur,  lift  the  paper  up  again  by  one 
corner,  and  remove  them  with  a  glass  rod,  or 
by  lifting  it  up  and  lowering  it  down  re- 
peatedly. 

The  paper  is  left  on  the  solution  for  about 
three  minutes,  after  which  one  corner  is  lifted 
up  with  a  strip  of  glass,  and  it  is  removed 
and  hung  up  to  dry,  using  for  this  purpose 
patent  clips  or  clothes  pins.  In  order  to 
make  it  dry  quicker,  it  is  advisable  to  remove 
the  superfluous  silver  from  the  surface,  by 
drawing  a  glass  rod  across  it. 

It  is  understood  that  the  sensitizing  and 
drying  are  to  be  done  in  a  dark  room,  that  is, 
in  a  room  out  of  which  the  chemical  light  has 
been  excluded.  A  room  with  yellow  or 
orange  panes  of  glass  in  the  windows,  or  with 
orange  paper  or  muslin  stretched  before  them, 
will  be  found  a  more  convenient  place  to 
operate  in,  than  a  real  dark  room  from  which 
all  natural  light  is  excluded,  and  which  is 
only  lighted  by  a  lamp  or  a  candle. 

When  the  paper,  after  sensitizing,  is  fumed 
with  ammonia,  the  formula  for  the  silver  solu- 
tion is  as  follows : 

Nitrate  of  silver,  1  ounce. 

Water,  9  ounces  fluid. 

Alcohol,  3  ounces  fluid. 

Nitric  acid,    2  drops. 


150 

The  manipulatory  details  are  the  same  as 
described  above. 

The  sensitized  paper,  being  dry,  is  then 
fumed  with  ammonia.  This  is  done  in  what 
is  called  a  fuming  box.  V arious  models  of 
fuming  boxes  have  been  proposed.  The  one 
we  prefer  is  made  on  the  same  plan  as  the 
old  daguerreotype  coating  boxes.  It  is  com- 
posed of  an  oblong  box,  twenty  by  twenty- 
four  inches,  and  about  twelve  inches  deep,  with 
a  cover  fastened  to  it  by  hinges.  In  the  bot- 
tom is  put  a  saucer  filled  with  concentrated 
ammonia,  Near  the  top  is  a  board  which  can 
be  slid  out  and  in.  The  sensitized  paper  is 
tacked  on  the  inside  of  the  cover,  which  is 
shut  down  and  the  board  pulled  out.  The 
ammonia  gas  which  had  collected  in  the  space 
between  the  bottom  and  the  slide,  will  fill  the 
upper  part  of  the  box,  and  act  upon  the  paper 
tacked  on  the  cover.  After  ten  or  fifteen  min- 
utes, the  slide  is  shut,  and  the  paper  taken 
off  when  it  is  ready  for  printing. 

The  ammonia  used  should  be  of  the  most 
concentrated  kind,  known  as  liquid  ammonia 
cone.  It  contains  in  solution  as  much  ammo- 
nia gas  as  it  will  hold  at  a  low  temperature. 
It  should  be  kept  in  a  cool  place,  and  opened 
with  great  care,  as  accidents  often  occur  from 
a  portion  of  the  liquid  being  thrown  out  forci- 
bly, upon  the  removal  of  the  stopper,  when  at 
all  warm. 

The  paper  can  be  over-fumed  or  under- 


151 


fumed.  When  over-fumed  it  is  more  or  less 
discolored,  prints  of  a  slaty  blue,  and  tones 
out  of  a  cold  steel  color.  When  under-famed 
it  prints  red  and  without  vigor,  and  is  diffi- 
cult to  bring  to  a  good  tone.  Paper  properly 
fumed  prints  vigorous  and  of  a  black  color, 
verging  slightly  on  the  red,  and  tones  to  a 
warm  black  tone. 

Fumed  paper  keeps  perfectly  well  for  two 
or  three  days,  and  is,  in  fact,  not  more  apt  to 
turn  yellow  than  the  paper  prepared  on  a 
strong  solution  of  silver,  and  not  fumed.  In 
damp  and  warm  weather,  it  is  advisable,  bow- 
ever,  to  keep  either  kind  in  a  chloride  of  cal- 
cium box,  where  it  remains  perfectly  dry,  and 
can  be  preserved  for  weeks  and  even  months. 
This  apparatus  consists  of  a  zinc  or  a  well 
varnished  wooden  box,  with  a  tight  fitting 
cover.  In  the  bottom  of  this  box  is  a  sheet 
iron  pan,  filled  with  dry  chloride  of  calcium. 
This  salt  absorbs  moisture  with  great  avidity, 
and  is  for  this  reason  used  as  a  dessicatiner 
agent  in  chemical  operations.  Above  the 
iron  pan,  and  resting  on  a  border,  is  a  wire 
frame,  on  which  is  laid  the  sensitive  paper. 
The  box  should  be  kept  open  as  little  as  pos- 
sible, to  keep  out  the  moisture.  After  being 
used  some  time,  the  chloride  of  calcium  be- 
comes wet  When  this  happens,  take  out 
the  sheet  iron  pan  containing  it,  and  warm  it 
on  a  stove  until  the  salt  is  again  dry.  This 


152 

operation  can  be  done  over  and  oyer  again, 
without  the  salt  losing  its  properties. 

Before  concluding  this  chapter  we  will  have 
to  say  a  few  words  on  a  subject  which  has 
lately  elicited  much  discussion  among  pho- 
tographic writers,  to  wit :  The  effect  of  the 
addition  of  nitrate  of  soda  to  the  silver  bath. 
It  is  claimed  that  the  addition  of  a  certain 
quantity  of  these  salts  produces  an  effect 
similar  to  that  of  fuming  the  paper  with  am- 
monia ;  that  is,  allows  the  use  of  a  weaker 
bath.  This  assertion  is  made  on  apparently 
good  authority,  while  equally  good  authority 
regard  the  whole  matter  as  absurd. 

In  our  hands  the  mixed  bath  of  nitrate  of 
silver  and  of  soda  has  not  produced  any  bet- 
ter results  than  the  silver  bath  used  without 
this  admixture.  A  series  of  experiments, 
undertaken  at  different  periods,  with  different 
solutions,  and  with  different  kinds  of  paper, 
has  forced  us  to  come  to  the  conclusion  that 
no  advantage  arises  from  the  use  of  the  above 
named  salt,  either  as  regards  intensity,  rap- 
idity or  tone,  or  freedom  from  mealiness  or 
toning  accidents. 

The  bath  containing  nitrate  of  soda  always 
gave  a  redder  print  on  removal  from  the 
printing  frame  than  the  plain  silver  solution : 
but  both  prints  were  brought  to  the  same 
color  in  the  toning  bath. 

Mr.  Henry  Anthony  recommends  the  use 
of  oxide  of  silver,  dissolved  in  nitrate  of  am- 


153 


monia,  for  the  silvering  of  paper.  The  prints 
obtained  by  this  process  equal  those  on  paper 
fumed  with  ammonia,  the  strength  of  the  sil- 
ver solution  being  the  same. 

The  way  to  proceed  is  as  follows  :  Dissolve 
one  ounce  of  nitrate  of  silver  in  three  or  four 
ounces  of  water,  and  about  one  ounce  of  caus- 
tic potash  in  two  or  three  ounces  of  water, 
and  mix  the  two  solutions  together ;  a  precipi- 
tate w^ill  be  formed,  which,  in  a  few  minutes, 
will  settle  to  the  bottom.  The  liquid  is  then 
poured  off  carefully,  a  fresh  quantity  of  water 
is  added,  and  after  the  oxide  of  silver  has 
again  subsided,  the  water  is  again  poured  off. 
In  this  way  the  oxide  of  silver  is  washed  care- 
fully five  or  six  times,  after  which  crystallized 
nitrate  of  ammonia  is  added,  a  few  drachms 
at  a  time,  until  all  but  a  small  quantity  of 
the  oxide  of  silver  is  dissolved.  Finally,  the 
solution  is  brought  to  a  bulk  of  twelve  ounces, 
by  the  addition  of  three  ounces  alcohol  and  a 
sufficient  quantity  of  water.  It  is  also  ad- 
visable to  add  a  few  drops  of  nitric  acid. 


CHAPTER  XXVIII, 

The  Printing. 

Printing  frames  of  different  forms  are  used 
by  photographers.  They  are  constructed  in 
such  a  way  that  the  picture  can  be  examined, 


154 


without  its  position  being  disturbed.  In  some, 
the  negative  is  laid  in  the  frame,  collodion 
side  uppermost,  the  sensitive  paper  is  then 
placed  upon  it,  then  a  piece  of  black  cloth  is 
laid  upon  the  paper,  the  shutter  is  placed 
upon  the  black  cloth,  and  the  whole  is  pressed 
together  by  means  of  two  springs.  In  other 
frames  of  a  different  construction,  the  paper  is 
laid  upon  the  frame,  and  the  negative  is  placed 
on  it,  and  is  kept  pressed  down  by  means  of 
springs.  It  is  essential  that  the  pressure  be 
equal  everywhere,  so  that  the  paper  be  in 
close  contact  with  every  part  of  the  negative. 

The  paper  should  be  perfectly  dry  before  it  is 
used,  if  not,  it  might  spoil  the  negative,  mainly 
when  this  has  been  gummed,  and  it  will  print 
of  a  reddish  color  in  the  spots  where  it  is  moist. 

The  preliminary  preparations  for  the  print- 
ing may  be  done  in  diffused  light,  unless  the 
light  be  so  strong  and  the  chloro-nitrate  of 
silver  so  sensitive  as  to  cause  the  paper  to 
darken,  which  is  very  seldom  the  case.  Weak 
negatives  should  be  printed  by  diffused  light ; 
negatives  of  good  intensity  may  be  printed  in 
sunlight,  except  when  the  heat  is  very  strong, 
in  which  case  the  varnish  might  soften  and  the 
glass  will  be  in  danger  of  cracking.  The 
printing  frame  should  be  laid  in  such  a  posi- 
tion as  to  cause  the  rays  of  light  to  fall  per- 
pendiculary  on  the  plate. 

The  time  of  exposure  is  very  variable ;  it 
depends,  1st,  on  the  sensitiveness  of  the  pa- 


155 


per ;  2d,  on  the  strength  of  the  light ;  3d,  on 
the  intensity  of  the  negative.  The  print 
should  be  taken  out  when  it  appears  slightly 
darker  than  it  is  intended  to  remain,  the 
toning  and  fixing  reducing  its  intensity.  A 
little  practice  will  soon  teach  the  operator  how 
far  the  printing  has  to  be  pushed. 

On  removal  from  the  printing  frame,  plain 
paper  silvered  with  ammonia-nitrate,  is  gen- 
erally black  or  purplish  black.  So  is  the 
same  paper  when  silvered  and  then  fumed. 
The  addition  of  citrate  of  soda  to  the  salting 
gives  it  a  slight  red  tinge.  Albumen  paper 
prepared  with  strong  silver,  prints  slightly 
red.  When  prepared  with  weak  silver  and 
fumed,  it  has  a  greater  tendency  to  the  black. 
When  prints  come  out  of  the  printing  frame 
too  red,  the  probability  is  that  the  silver  is 
too  weak ;  or  that  the  paper  has  not  been 
sufficiently  fumed. 

When,  on  removal  from  the  printing  frame, 
the  paper  remains  white  in  certain  parts,  or 
is  covered  with  white  spots,  it  is  a  proof 
that  all  the  alkaline  chloride  has  not  been 
transformed  into  chloride  of  silver,  which 
may  result  from  the  silver  solution  being  too 
weak,  or  from  the  paper  not  having  been  left 
on  it  a  sufficient  time,  or  also  from  imperfect 
silvering  with  the  brush. 


156 


CHAPTER  XXIX. 

Toning,  Fixing,  Washing,  and  Mounting  of  the  Prints. 

The  toning  and  fixing  are  two  very  impor- 
tant operations  in  the  production  of  the  pho- 
graphic  print.  If  the  intensity  and  vigor, 
and,  to  a  certain  extent,  the  tone  of  the  print, 
depend  on  the  preparation  of  the  sensitive 
paper,  the  permanency  depends  principally 
on  the  toning  and  fixing. 

It  is  but  a  short  time  since  the  process  of 
toning  and  fixing  together  was  in  general  use. 
Toning  properties  were  communicated  to  the 
fixing  solution  either  by  repeated  use,  or  by 
the  addition  of  various  substances,  such  as 
acids,  iodine,  chloride  of  gold,  chloride  of  sil- 
ver, etc.  In  all  cases,  except  when  chloride 
of  gold  was  used  in  connection  wdth  a  new 
hyposulphite  solution,  the  red  color  of  the 
photograph  was  altered  by  a  combination  of 
the  silver  compound  with  sulphur,  which,  in 
the  hyposulphites,  is  but  loosely  combined. 
This  sulphur  and  silver  compound  is  very 
unstable,  and  is  acted  upon  by  air,  moisture, 
acid,  etc.  causing  the  lading  of  the  photo- 
graph. When  gold  was  used  in  a  new  hypo- 
sulphite bath,  the  first  prints  were  toned  by 
gold,  but  after  being  used  some  time,  the  bath 
would  acquire  also  the  property  of  sulphur 
toning,  so  that  this  process  was  in  the  main 
not  more  reliable  than  the  others. 


157 


The  method  universally  adopted  now,  is 
the  toning  and  fixing  of  the  prints  separately. 
This  method  is  at  the  same  time  safer,  more 
economical,  more  expeditious,  and  gives  re- 
sults superior  to  those  used  before. 

The  operations  to  be  performed  to  finish 
the  print,  after  it  is  removed  out  of  the  print- 
ing frame,  are  as  follows  : 

1st,  Washing  to  get  rid  of  the  free  nitrate 
of  silver. 

2d,  Toning. 

3d,  Washing  to  remove  the  toning  solution. 
4th,  Fixing. 

5th,  Washing  to  remove  the  hyposulphite. 

On  removal  from  the  printing  frames,  the 
prints  are  put  away  in  a  box  or  in  the  dark 
room ;  or,  better  yet,  in  a  chloride  of  calcium 
box,  and  kept  there  until  a  sufficient  number 
are  collected  to  begin  the  toning  and  fixing. 
The  use  of  the  chloride  of  calcium  box  is  to 
be  recommended  in  damp  and  warm  weather, 
and  whenever  the  prints  have  to  be  kept 
longer  than  a  few  hours. 

When  ready  to  be  toned,  the  prints  are  put 
in  a  tray  with  water,  to  soak  out  the  free  ni- 
trate of  silver.  After  five  or  ten  minutes, 
the  water  is  poured  out,  and  the  tray  is  again 
filled  up  with  fresh  water.  This  operation 
should  be  repeated  three  or  four  times,  so  as 
to  remove  all  the  free  nitrate.* 

*  See  Chapter  on  "  Recovery  of  Silver  in  Photographic 
Operations." 


158 


The  toning  bath  is  prepared  according  to 
the  following  formula : 

Water,   40  ounces. 

Chloride  of  sodium,  20  grains. 

Bicarbonate  of  soda,  . .  » . . .  2  grains. 

Chloride  of  lime,   2  grains. 

Solution  of  chloride  of  gold  sufficient  quantity. 

The  solution  of  chloride  of  gold  is  made 
by  dissolving  fifteen  grains  of  the  pure  chlo- 
ride in  one  pint  of  water  ;  or  a  one  dollar 
gold  piece*  in  forty  ounces  of  water. 

The  chloride  of  sodium  or  common  salt  is 
added  to  the  toning  bath  to  transform  into 
chloride  the  nitrate  of  silver  which  may 
remain  in  the  prints,  and  which  would  other- 
wise decompose  the  chloride  of  gold. 

The  bicarbonate  of  soda  has  the  effect  of 
causing  the  chloride  of  gold  to  yield  more 
readily  the  metallic  gold  to  the  prints.  An 
excess  of  this  salt  should  be  guarded  against, 
or  after  a  short  time  a  double  salt  of  gold  and 
soda  would  be  formed,  which  does  not  possess 
toning  properties. 

The  addition  of  a  small  quantity  of  chlo- 
ride of  lime  to  the  toning  bath  improves  it 
considerably.  Black  tones  and  pure  whites 
seem  to  be  more  easily  produced.    The  chlo- 


*  A  one  dollar  gold  piece  can  be  dissolved  in  four  drachms 
of  a  mixture  of  one  part  nitric  and  three  parts  hydrochloric 
acid,  then  diluted  with  three  or  four  ounces  of  water  ';  after 
which  a  strong  solution  of  carbonate  of  soda  is  added  a 
little  at  a  time,  until  a  green  precipitate  of  carbonate  of 
copper  is  formed.  The  solution  is  then  filtered  and  diluted 
with  sufficient  water  to  measure  forty  ounces. 


159 


ride  of  lime  possesses  great  advantages  when- 
ever the  paper,  for  some  reason  or  other,  is 
discolored. 

The  quantity  of  chloride  of  gold  solution 
to  be  added  depends  entirely  on  the  number 
of  prints  to  be  toned.  Fifteen  grains  of  the 
pure  chloride  should  tone  about  ten  sheets 
photographic  paper,  and  the  solution  made 
with  a  dollar  gold  piece  should  tone  about 
twenty  sheets.  Whenever  but  a  small  number 
of  prints  have  to  be  toned,  it  is  preferable  to 
add  the  necessary  quantity  of  gold  to  a  smaller 
quantity  of  the  bath. 

The  toning  bath  should  have  been  pre- 
pared a  short  time  before  being  used,  for  if 
too  fresh  it  is  apt  to  produce  mealiness.  One 
made  according  to  the  formula  given  above, 
will  work  best  an  hour  or  two  after  it  has 
been  mixed.  If  it  should  lose  its  energy 
before  all  the  prints  are  toned,  more  of  the 
gold  solution  should  be  added. 

The  prints  are  taken  out  of  the  water,  and 
immersed  in  the  toning  bath,  where  they  are 
kept  in  motion  during  the  whole  process  of 
toning.  They  may  at  first  get  slightly  redder, 
but  they  will  afterwards  pass  through  all  the 
intermediate  stages,  between  the  color  they 
have  on  immersing  and  the  blue  black.  The 
toning  can  be  stopped  at  any  stage  by  im- 
mersing the  print  in  a  tray  of  clear  water, 
kept  on  hand  for  the  purpose.  The  real  color 
of  the  print  is  only  seen  after  the  immersion 


160 


in  the  hyposulphite  fixing  solution,  so  that 
the  operator  will  have  to  discern  to  what  tint 
the  print  should  be  brought  to  assume,  after 
fixing  the  color  he  wants.  As  a  general  thing 
the  bluish  black  changes  to  a  pure  black  in 
the  hyposulphite  ;  less  toning  than  is  required 
to  give  the  bluish  black  produces  prints  more 
or  less  brown  ;  if  the  toning  is  pushed  fur- 
ther, the  prints  are  liable  to  be  bluish  and 
ashy  colored  when  dry.  This  holds  good  for 
plain  or  for  albumen  paper.  Albumen  paper 
silvered  and  fumed,  tones  much  easier  and  is 
less  liable  to  mealiness  than  the  one  which 
has  not  been  fumed ;  the  same  can  be  said  of 
albumen  paper  prepared  on  the  solution  of 
oxide  of  silver  in  nitrate  of  ammonia.  If  a 
large  number  of  prints  have  to  be  toned,  the 
toning  bath  should  of  course  be  made  larger ; 
but  in  most  cases  it  would  be  hardly  neces- 
sary to  use  more  than  a  quart  or  three  pints 
of  solution.  The  gold  necessary  for  the  ton- 
ing should  not  be  used  all  at  once,  but  one  or 
two  ounces  of  the  solution  at  one  time.  In 
this  way  is  avoided  a  too  rapid  action,  which 
most  always  brings  with  it  spots  or  mealiness 
on  albumen  paper. 

The  time  necessary  for  toning  an  albumen 
print  should  be  from  two  to  five  minutes. 
Prints  on  plain  paper,  fumed  or  silvered  with 
ammonia-nitrate,  tone  much  quicker. 

The  toning  bath  may  be  used  over  and  over 
again,  by  adding  a  fresh  supply  of  gold,  if 


161 


care  be  taken  to  avoid  the  introduction  of 
hyposulphite.  The  effect  of  the  introduction 
of  hyposulphite  in  the  toning  bath,  is  to 
make  it  lose  its  energy. 

The  prints,  as  soon  as  they  are  taken  out  of 
the  toning  bath,  are  immersed  in  water. 
They  are  then  washed  several  times  and  put 
into  the  fixing  bath,  which  is  composed  as 
follows : 


The  fixing  will  not  require  more  than  ten 
minutes.  It  is  done  when  the  paper  presents, 
by  transmitted  light,  an  uniform  appearance, 
showing  no  opaque  spots  of  undissolved  chlo- 
ride of  silver. 

The  fixing  solution  will,  by  being  used,  ac- 
quire toning  properties  which  are  very  objec- 
tionable, as  they  are  due  to  liberation  of  sul- 
phur. The  operator  should  thus  not,  for  rea- 
sons of  economy,  use  this  solution  too  often, 
and  in  such  way  endanger  the  permanency  of 
his  prints.  The  above  given  quantity  can  be 
used  to  fix  about  sixty  4-4  size  prints. 

On  immersion  in  the  hyposulphite,  the  real 
color  of  the  print  shows  itself  immediately. 
Prints  toned  to  black  change  very  little  during 
the  fixing ;  those  which  are  less  toned  become 
slightly  redder. 

Different  Formulae  for  Toning  Baths. 

A  great  variety  of  toning  baths  are  used 


Hyposulphite  of  soda, 
>Bi-carbonate  of  soda. 
Water,  


8  ounces. 
1  drachm. 
32  ounces  fluid. 


162 


by  photographers,  and  each  one  is  claimed  to 
"be  superior  to  the  other.  The  one  we  have 
given  above  is  very  simple,  and,  we  are 
inclined  to  think,  will  produce  as  good  results 
as  any.  We  are  not  prepared  to  pronounce 
on  the  value  of  the  use  of  the  different  sub- 
stances claimed  to  possess  peculiar  virtues  in 
the  toning,  for  want  of  well  attested  facts  on 
wilich  to  base -our  opinion.  We  will  confine 
ourselves  here  to  giving  a  number  of  formulae 
recommended  by  the  most  successful  operators. 

Toning  Bath  with  Citrate  of  Soda  (Hardwich). 

Bi-carbonate  of  soda  240  grains. 

Citric  acid  160  grains. 

Water     1  quart. 

Chloride  of  gold,  lj^  grains  to  a  sheet  of  albumen  paper. 

In  making  this  solution,  an  effervescence 
will  be  produced,  resulting  from  the  freeing 
of  carbonic  acid.  When  it  has  ceased,  the 
combination  of  the  citric  acid  with  the  soda 
has  taken  place,  and  the  liquid  contains  citrate 
of  soda  with  an  excess  of  bi-carbonate  of  soda. 

Maxwell  Lyle's  Formula. 


Water  32  ounces. 

Phosphate  of  soda   %  ounce. 

Chloride  of  gold  as  above. 

Formula  with  Acetate  of  Soda. 

Water   ...  .32  ounces, 

Acetate  of  soda  %,  ounce. 

Phloride  of  gold  as  above. 

Chloride  of  Lime  Bath. 

Chloride  of  lime  (hypochlorite  of  lime)  5  grains. 

"Water  -  32  oanoee. 

Chloride  of  gold  as  above. 


163 


Nitrate  of  Uranium  Bath. 


Nitrate  of  uranium  

Acetate  of  soda  

Water  

Chloride  of  gold  as  above. 


60  grains . 
120  grains. 
.  32  ounces 


Carbonate  of  Lime  Bath. 


Precipitated  or  pulverized  chalk 

Chloride  of  calcium  

Water  

Chloride  of  gold  as  above. 


120  grains. 
24  grains. 
32  ounces. 


For  all  these  baths  the  chloride  of  gold 
should  be  neutral.  If  acid,  a  few  grains  of 
bi-carbonate  of  soda  should  be  added  to  the 
toning  bath. 

The  washing  is  another  point  of  great 
importance.  To  insure  the  permanency  of 
the  prints,  it  is  essential  to  wash  out  all  the 
hyposulphite  of  soda  they  contain.  The 
methods  of  washing  used  by  photographers 
are  various,  and  depend  a  great  deal  on  local 
conveniencies  and  the  quantity  of  water  of 
which  they  dispose.  The  most  simple  method 
is  to  have  several  trays  filled  with  water,  and 
to  change  the  prints,  one  at  a  time,  from  one  tray 
into  another,  leaving  them  ten  or  fifteen  min- 
utes in  each.  Mr.  Shadbolt  proposes  to  drain 
the  prints  every  time  they  are  changed.  If 
this  is  done  the  washing  will  be  a  great  deal 
more  effectual.  What  is  better  yet,  is  to  pass 
them,  after  each  washing,  through  one  of  the 
patent  clothes  wringers.  In  this  way  the  larger 
quantity  of  the  water  is  pressed  out  between 
the  rollers,  and  the  print  comes  out  nearly 


164 


dry.  These  clothes  wringers  are  invaluable 
to  amateurs,  who  make  only  a  small  number 
of  prints,  but  the  manual  labor  they  require 
make  them  not  so  well  adapted  to  the  use  of 
professional  photographers,  who  have  large 
numbers  of  prints  to  wash.  Another  draw- 
back to  the  use  of  the  clothes  wringer  is,  that 
the  prints  require  to  be  made  on  strong  Saxe 
paper,  the  Rive  and  other  papers  getting 
injured  during  the  operation. 

An  excellent  way  of  washing,  but  which 
can  only  be  practiced  in  cities  where  water- 
works exist,  is  to  lay  the  prints  on  a  coarse 
muslin  screen  stretched  on  a  frame,  and  allow 
the  water  to  sprinkle  over  them  through  the 
head  of  a  watering  pot  fixed  to  the  hydrant 
by  means  of  a  vulcanized  rubber  tube.  This . 
screen  or  frame  should  be  laid  inclined,  so  as 
to  allow  the  water  to  run  off  easily.  The 
greater  the  pressure  of  the  column  of  water, 
the  more  effectual  the  washing  will  be.  The 
position  of  the  print  should  be  frequently 
changed.  By  combining  this  method  with 
that  of  Mr.  ^Shadbolt,  that  is,  allowing  the 
prints  to  drain  from  time  to  time  while  on  the 
screen,  a  very  effectual  cleansing  is  obtained. 

Some  operators  lay  the  prints  flat  on  a 
piece  of  thick  plate  glass  under  a  stream  of 
water,  and  press  them  with  a  sponge,  or  roll 
them  with  a  thick  glass  tube.  Either  of  these 
two  last  ways  are  effectual,  but  they  entail  too 
much  labor. 


165 


Messrs.  T.  E.  &  C.  Bull,  of  London,  con- 
structed a  print  washing  apparatus  in  which 
the  consecutive  washing  and  draining,  recom- 
mended by  Mr.  GL  Shadbolt,  are  performed  au- 
tomatically. It  is  composed  of  a  tub  with  a  false 
bottom  at  about  half  the  height.  This  false 
bottom  is  made  of  zinc  or  wood,  and  is  per- 
forated with  holes.  A  syphon  of  wide  diame- 
ter is  put  either  in  the  middle  or  at  the  side, 
at  such  a  height  that  when  the  tub  is  lilled  up 
with  water,  the  syphon  is  started,  and  the 
water  is  rapidly  discharged,  leaving  the  prints 
on  the  false  bottom,  where  they  drain  until 
there  is  again  sufficient  water  in  the  tub  to  lift 
them  off.  The  stream  of  water  is  directed  so 
as  to  strike  the  side  of  the  tub  slanting ;  in 
this  way  a  rotary  motion  is  given  to  the  water, 
which  prevents  the  prints  from  sticking 
together,  and  keeps  them  rolling  and  turning 
around. 

The  Rive  and  some  other  kinds  of  paper 
are  very  apt  to  get  injured  during  this  opera- 
tion ;  and  when  the  prints  are  of  large  size, 
even  the  strong  Saxe  paper  gets  broken  and 
torn. 

Mr.  Hanbury  has  recently  brought  out  a 
washing  apparatus,  which  we  think  is  the 
best  one  yet  made.  It  consists  of  a  cradle 
about  eight  feet  long,  two  feet  wide,  and  two 
feet  deep.  In  the  middle  is  a  partition  which 
divides  it  in  two,  thus  forming  two  troughs, 
two  feet  wride  and  two  feet  deep.    The  cradle 


166 


is  balanced  in  the  middle  on  an  axis,  and  can 
tip  down  about  six  inches  either  on  one  side 
or  on  the  other.  The  water-cock  is  disposed 
over  the  cradle  in  such  a  way,  that  when  the 
right  hand  compartment  is  down,  the  water 
runs  in  the  left  hand  compartment,  and  vice 
versa.  At  the  end  of  each  compartment,  and 
at  two  or  three  inches  from  the  top,  is  a 
syphon,  which,  as  the  water  reaches  its  upper 
extremity,  is  started  and  the  water  discharged. 
On  the  side  of  the  cradle  and  running  the 
whole  length  of  it,  is  an  oblong  water-tight 
box,  about  four  inches  square,  which  is  kept 
half  filled  with  water.  Let  us  suppose  that 
the  right  hand  compartment  is  down,  so  that 
the  water  is  being  discharged  through '  the 
syphon,  and  the  water  in  the  water-box  is 
in  the  right  hand  side.  The  water  thus  runs 
into  the  left  hand  compartment,  and  as 
soon  as  its  weight  is  sufficient  to  overcome 
the  weight  of  the  water  in  the  water-tight 
box,  the  cradle  will  tip  down,  the  syphon  will 
be  started,  the  water  in  the  box  will  flow  to  the 
left  hand  side,  and  the  right  hand  compart- 
ment will  come  under  the  water-cock.  Then 
the  same  operation  will  be  repeated  on  the 
right  hand  side,  etc.  The  quantity  of  water 
in  the  box  should,  of  course,  be  regulated  by 
experiment,  to  balance  exactly  the  quantity 
of  water  in  each  trough,  when  filled  up  to 
about  six  inches  from  the  upper  part  of  the 
syphon.    It  may  be  necessary  to  have  the 


167 


water  box  longer  than  the  cradle,  so  that  the 
water  be  further  from  the  center  of  gravity. 

Each  trough  can  be  filled  with  a  false  bot- 
tom, like  in  Bull's  washing  machine ;  or  the 
prints  can  be  hung  perpendicularly  in  the 
water,  in  which  case  the  false  bottom  is  use- 
less. 

The  prints  have  to  be  washed  until  the 
whole  of  the  hyposulphite  is  removed.  The 
different  tests  for  hyposulphite  are  not  suffi- 
ciently delicate  to  be  of  use,  quantities 
of  hyposulphite,  which  are  inappreciable  to 
these  tests,  being  sufficient  to  cause  the 
fading  of  the  print.  It  is  thus  impossible  to 
say  how  long  a  print  should  be  washed.  The 
great  points  to  be  attended  to,  no  matter  what 
system  of  washing  be  used,  are  :  1st,  That 
the  prints  be  drained  from  time  to  time,  to 
discharge  most  of  the  water  they  hold  ;  and, 
2d,  That  they  be  kept  well  separated,  so  that 
the  hyposulphite  be  able  to  diffuse  itself  into 
the  water.  We  are  inclined  to  think  that 
when  these  conditions  are  observed,  ten  or 
fifteen  changes  of  water,  either  by  hand  or  by 
the  use  of  any  of  the  washing  apparatus  de- 
scribed, are  sufficient. 

The  prints  being  well  washed  are  hung  up 
to  dry,  either  by  means  of  clips  or  patent 
clothes  pins.  When  the  paper  will  stand  it, 
they  may  be  passed  through  a  patent  clothes- 
wringer.  They  can  also  be  dried  between 
sheets  of  blotting  paper. 


108 


Mounting  of  the  Prints. 

The  print  is  first  properly  trimmed  to  the 
required  size.  To  do  this,  it  is  laid  on  a 
piece  of  glass,  another  piece  of  glass  of  the 
form  and  shape  of  the  print  is  laid  on  it,  and 
a  sharp  knife  is  passed  along  the  edges  of  the 
glass.  Brass  or  tin  mats  are  also  used  for  trim- 
ming, the  point  of  the  knife  being  then  passed 
along  the  inside  of  the  mat. 

The  paste  used  generally  is  made  with 
starch  or  flour.  Grum  arabic,  dextrine,  and 
gelatine  can  also  be  used.  Starch  flour, 
gum  arabic,  and  dextrine  paste  become  acid 
by  keeping.  They  should  thus,  as  much  as 
possible,  be  used  fresh. 


CHAPTER  XXX. 

On  the  Fading  of  Positive  Prints. 

When  the  sensitive  paper  has  been  acted 
upon  by  light,  the  image  is  supposed  to  be 
free  of  silver  and  organic  matter.  After  im- 
mersion in  a  solution  of  salt,  the  nitrate  is 
transformed  into  chloride,  which  is  afterwards 
dissolved  in  the  hyposulphite.  If  without 
being  toned  the  print  is  immersed  in  a  solu- 
tion of  hyposulphite,  the  composition  of  the 
image  will  be  very  little  affected.  Prints 
treated  this  way  are  permanent. 

When  the  print  is  fixed  in  a  bath  which, 


169 


through  unskillful  management  or  otherwise, 

contains  sulphuretting  principles,  the  image 
in  composed  of  silver,  organic  matter  and 
sulphur.  Experience  has  shown  that  this 
compound  is  less  permanent  than  the  other, 
f specially  under  the  influence  of  moisture. 

If  the  print  before  being  fixed  is  immersed 
in  a  solution  of  chloride  of  gold,  the  chlorine, 
which  is  combined  with  the  gold,  will  pass  to  the 
silver,  forming  pro  to-chloride  of  silver  in  the 
middle  tints,  and  sub-chloride  of  silver  in  the 
deep  shades,  while  the  gold  is  deposited  in  the 
metallic  state.  On  immersion  in  the  hyposul- 
phite of  soda,  the  sub-chloride  of  silver  is  de- 
composed in  metallic  silver  and  proto-chlor- 
ide  of  silver,  and  the  proto-chloride  is  dissolved. 
The  image  in  this  case  is  thus  composed 
of  gold,  silver  and  organic  matter,  the  gold 
predominating  when  the  toning  has  been 
pushed  far.  Prints  toned  this  way  have  stood 
the  destructive  tests  better  than  any  other, 
mainly  when  containing  much  gold. 

In  the  gold  fixing  and  toning  bath  the  print 
goes  through  several  changes  which  have  not 
been  very  well  explained,  and  which  result  in 
the  image  being  composed  of  silver,  sulphur, 
gold  and  organic  matter.  The  better  the  sup- 
ply of  chloride  of  gold  is  kept  up,  the  more 
gold  and  the  less  sulphur  the  prints  contain. 
Prints  toned  in  the  gold  fixing  and  toning  bath 
are  less  permanent  than  those  toned  with  gold 
and  fixed  with  plain  hyposulphite. 

15 


170 


1 


When  to  a  solution  of  hyposulphite  of  soda 
an  addition  of  acid  of  any  kind  is  made,  hy- 
posulphite is  decomposed,  and  sulphur  is  set 
free,  by  which  the  prints  which  are  immersed 
nnto  it  will  be  toned. 

m  The  addition  of  iodine,  per-chloride  of  iron, 
nitrate  and  chloride  of  silver,  etc.,  to  the  hypo- 
sulphite solution,  produce  in  it  unstable  salts 
which  have  sulphurating  properties.  It  is  to 
the  addition  by  constant  use  of  the  nitrate  and 
chloride  of  silver  that  the  plain  fixing  solu- 
tion acquires  the  property  of  darkening  the 
image. 

The  presence  of  sulphur  in  the  photographic 
print  being  one  of  the  main  causes  of  its  fad- 
ing, we  have  to  discard  all  processes  in  which 
it  is  used  as  a  toning  agent.  These  pro- 
cesses, as  we  have  seen,  already,  are,  1st, 
The  hyposulphite  bath  which  has  acquired 
toning  properties  by  being  used.  2d,  The 
one  to  which  acid  has  been  added.  3d,  Those 
made  with  iodine,  per-chloride  of  iron,  et  c.  4thf 
The  gold  fixing  and  toning  bath.  The  last 
one  is  the  least  objectionable  when  the  supply 
of  gold  is  well  kept  up,  as  in  this  case  the 
quantity  of  sulphur  in  the  print  is  very  small. 

Besides  the  presence  of  sulphur  in  the  print, 
fading  may  be  produced  by  the  following 
causes : 

Imperfect  washing. — It  is  important  that  th 
least  trace  of  hyposulphite  of  soda  should  be 
washed  out  of  the  paper.    The  water  giving 


171 


no  precipitate  with  nitrate  of  silver  or  bi-chlo- 
ride  of  mercury,  is  no  proof  that  the  print  is 
sufficiently  washed,  as  none  of  these  salts  are 
tests  for  a  very  small  quantity  of  hyposulphite. 
The  presence  of  hyposulphite  in  the  print 
causes  it  to  become  yellow  firstly  in  the  half 
tints,  and  afterwards  in  the  shadows. 

Prints  properly  toned  by  gold  are  less  af« 
felted  by  a  minute  quantity  of  hyposulphite 
than  those  toned  by  sulphur,  which  in  a  short 
time  are  entirely  destroyed. 

Moisture  and  impure  air, — Moisture  is  al- 
-  ways  a  condition  favorable  to  decomposition. 
If  the  print  has  not  been  properly  toned, 
the  fading  will  go  on  very  rapidly  under  its 
influence.  Prints  toned  by  gold  and  well 
washed  resist  the  effect  of  dam])  air  quite  as 
well  as  engravings.  But  when  air,  besides 
being  damp,  contains  sulphuretted  hydrogen, 
sulphuric  acid,  etc.,  (products  of  the  combustion 
of  coal  and  coal  gas,)  no  photograph  can  long 
resist  its  deleterious  effects. 

Acid  'paste  used  in  mounting, — Starch  and 
flour  paste  and  gum  arabic  become  sour  by 
keeping,  and  should  be  avoided,  even  when 
freshly  made,  as  the  acetous  fermentation 
which  produces  this  acidity  may  take  place 
after  the  photograph  is  mounted,  when  it  is 
exposedto  the  influence  of  moisture.  This 
acidity  is  very  destructive  to  prints  toned  by 
sulphur.  Its  effect  on  prints  toned  by  gold 
seems  to  be  very  limited. 


172 


Prints  developed  to  the  black  stage  and 
fixed  in  plain  hyposulphite  are  less  affected  by 
the  destructive  causes  spoken  of  above,  than 
those  which  have  not  been  pushed  further 
than  the  red  or  purple  stage  If  these  how- 
ever are  toned  in  the  gold  toning  bath,  they 
are  in  the  same  condition  as  direct  prints 
treated  the  same  way. 

The  toning  by  sulphur  of  developed  prints 
deposits  also  in  the  paper  the  substances  which 
cause  their  destruction. 


CHAPTER  XXXI. 

Instruments  used  for  Making  Enlarged  Prints  froj* 
Collodion  Negatives.— The  Solar  Camera. 

If  a  negative  be  put  in  a  camera  at  the 
place  occupied  by  the  plate  holder,  and  the 
camera  be  then  placed  in  a  hole  cut  in  a  dark 
room,  in  such  a  position  that  the  light  falls  on 
the  negative,  and  can  only  be  admitted  into 
the  dark  room  by  passing  through  the  nega- 
tive and  the  tube,  an  enlarged  image  will  be 
formed  at  some  distance  from  the  tube.  Sup- 
posing the  same  camera  to  have  been  used  to 
make  the  negative,  the  image  will  .be  of  the 
size  of  life,  if  the  negative  occupies  the  same 
position  as  when  it  was  made,  and  the  focus- 
sing screen  is  at  the  same  distance  from  the 
tube  as  the  sitter  was.    If  the  focussing  screen 


173 


be  brought  nearer  the  tube,  and  the  distance 
between  tube  and  negative  increased  so  that 
the  two  foci  correspond,  the  image  will  become 
smaller.  On  the  contrary,  if  the  distance  be- 
tween tube  and  screen  be  increased,  and  the 
one  between  negative  and  tube  be  decreased 
to  a  corresponding  focus,  the  image  will  be 
larger  than  life. 

It  will  be  remarked  that  in  this  arrange- 
ment the  position  of  the  tube  is  reversed,  so 
that  the  front  lens  is  nearest  the  focussing 
screen,  and  the  back  lens  nearest  the  nega- 
tive. This  is  the  disposition  to  be  adopted  in 
all  cases  where  copies  have  to  be  made  larger 
than  the  original. 

In  order  now  to  obtain  an  enlarged  print, 
all  that  is  necessary  is  to  put  a  sheet  of 
sensitive  paper  at  the  place  occupied  by  the 
focussing  screen. 

To  make  the  image  more  luminous  the  light 
of  the  sun  can  be  reflected  on  the  negative  by 
means  of  a  mirror.  The  mirror  should  be 
fixed  in  front  of  the  negative,  and  should  both 
swing  and  turn  on  a  pivot.  The  centers  on 
which  it  turns  and  swings  should  be  on  a  level 
with  the  axis  of  the  lens.  When  such  an  ar 
rangement  is  used,  the  box  should  face  the 
south  if  possible,  in  order  to  be  able  to  use 
0  sunlight  the  larger  part  of  the  day.  The  ne- 
gative should  be  covered  with  a  ground  glass 
so  as  not  to  have  the  disc  of  the  sun  reflected 
on  the  sensitive  paper. 


174 


The  solar  camera  is  an  instrument  express- 
ly made  for  the  printing  of  enlarged  images. 
It  is  constructed  on  the  same  principles  as  the 
apparatus  described  above,  but  has  in  addition 
to  it  a  bi-convex  or  plano-convex  lens,  of  a 
large  diameter,  on  which  the  light  is  reflected, 
and  which  condenses  it  and  brings  it  to  a 
focus  at  a  distance  of  twelve  or  fifteen  inches. 
The  reflector  is  a  plane  mirror,  a  little  wider 
than  the  condensing  lens,  and  about  three 
times  as  long  as  it  is  wide.  It  is  arranged  by 
means  of  two  movements  so  as  to  be  put  in  all 
positions,  and  follow  the  march  of  the  sun  so 
that  the  rays  may  be  always  reflected  perpen- 
dicularly to  the  condensing  lens.  The  tube 
used  may  be  either  a  portrait  combination  or 
a  view  lens.  A  diaphragm  with  a  small  aper- 
ture is  put  between  the  lenses  in  one  case,  or 
in  front  of  it  in  the  other,  and  the  box  is  made 
of  such  a  length  that  the  light  condensed  by 
the  bi-convex  or  plano-convex  lens  comes  to  a 
focus  at  the  spot  where  is  the  aperture  of  the 
diaphragm. 

The  negative  is  put  in  a  slide  which  is 
moved  forward  and  backward  by  means  of  a 
rack  work.  It  will  be  easily  understood  that 
the  nearer  the  negative  is  to  the  condensing 
lens,  the  larger  and  the  less  luminous  will  be 
the  disc  of  light  thrown  on  it,  and  the  nearer 
it  is  to  the  tube,  the  smaller  ancf  the  more 
luminous  it  will  be. 

The  solar  camera  should,  as  much  as  pos- 


175 


sible  face  the  south.    If  it  was  a  little  to  the 

east  or  to  the  west,  the  reflector  would  not  be 
found  long  enough  to  throw  the  sunlight  on  the 
entire  surface  of  the  condensing  lens  during 
the  whole  day  in  the  winter  months. 

When  the  large  size  solar  camera  is  used, 
is  convenient  to  have  two  single  lenses,  one  of 
about  eight  inches  focus,  and  the  other  of  about 
five  and  a  half  inches  ;•  or,  instead  of  these,  a  4-4 
and  a  half  size  portrait  combination.  In  con- 
nection with  a  small  size  solar  camera,  use  a 
lens  of  five  and  a  half  inches  focus,  and  another 
one  of  three  or  three  and  a  half  inches,  or  a 
half  size  and  a  quarter  size  portrait  tube. 
The  long  focus  lenses  or  combinations  of  lenses 
are  used  with  large  negatives,  and  the  short 
focus  ones  with  smaller  negatives. 

The  solar  camera  being  placed  in  the  hole 
cut  in  the  dark  room,  the  negative  is  put  in  one 
of  the  grooves,  and  the  focussing  screen  put  at 
a  certain  distance  from  the  tube.  It  is  to  be 
remarked  that  the  larger  the  image  has  to  be, 
the  further  the  focussing  screen  will  have  to 
be  in  the  dark  room,  and  the  nearer  the  nega- 
tive has  to  be  brought  toward  the  tube.  The 
image  is  brought  to  a  focus  by  moving  the  neg- 
ative without  touching  the  lens.  The  focus- 
ing should  be  done  by  diffused  light,  using 
the  whole  aperture  of  the  instrument,  with 
a  portrait  combination,  or  a  large  diaphragm 
with  the  single  lens.  A  diaphragm  of  half 
an  inch  or  quarter  of  an  inch  diameter, 


176 


is  then  adapted  at  the  place  where  the  rays  of 
light  comet)  a  focus,  and  the  sun  is  turned  on. 
We  will  remark  hare,  tint  in  this  combina- 
tion the  diaphragm,  when  it  is  pub  in  the  pro- 
per place,  does  not  cut  off  any  of  the  light,  all 
the  rays  emanating  from  the  negative  being 
condensed  to  a  point  at  the  spot  where  is  the 
aperture.  The  function  of  the  diaphragm  here 
is  to  increase  the  sharpness  of  the  image  and 
flatten  the  field,  and  to  cut  off  the  rays  which 
are  transmitted  through  the  parts  of  the  nega- 
tive not  covered  by  the  disc  of  condensed  light, 
and  those  which  are  reflected  from  the  sides  of 
the  box. 

In  order  not  to  have  in  the  dark  room  more 
light  than  is  necessary,  the  parts  of  the  nega- 
tive which  have  not  to  be  printed  should  be 
covered  with  a  mat.  The  observance  of  these 
recommendations  is  not  of  such  great  impor- 
tance when  the  direct  positive  process  is  used 
as  when  the  prints  are  made  by  development. 

The  stand  which  supports  the  focussing 
screen,  or  the  sensitive  paper,  should  be  per- 
fectly vertical,  and  rigorously  parallel  with 
the  negative  and  the  tube,  the  least  deviation 
causing  a  distortion  of  the  image.  The  sup- 
port on  which  the  solar  camera  rests  should 
also  be  perfectly  level.  To  insure  the  paral- 
lelism of  the  camera  and  the  stand,  the  opera- 
tor should  paint  a  series  of  parallel  lines  on 
the  floor  of  his  dark  room. 

The  stand  should  be  made  on  the  same 


177 


principle  as  a  painter's  easel.  It  should  have 
parallel  sides,  and  be  about  six  feet  high,  and 
two  and  a  half  feet  wide.  The  part  on 
which  the  focussing  screen  or  the  prepared 
surface  rests,  slides  up  and  down,  and  is 
fastened  with  a  catch.  The  stand  is  kept 
steady  by  means  of  a  brace. 


CHAPTER  XXXIV. 

Enlarged  Prints  by  the  Direct  Positive  Process. 

Negatives  used  in  this  process  should  have 
little  intensity,  and  be  well  marked  in  all  the 
details.  They  should  also  be  distinct  and 
clear  in  the  shadows,  without  great  contrast 
and  free  from  spots  and  marks.  To  insure 
these  conditions,  the  collodion  should  give  an 
even  and  structureless  film,  the  silver  bath 
should  be  in  a  condition  to  give  images  with- 
out the  least  fogginess ;  the  exposure  in  the 
camera  should  only  be  a  little  more  than  for 
a  collodion  positive,  and  the  image  should  be 
fully  developed.  The  negative  should  not  be 
varnished,  as  no  varnished  surface  is  free 
enough  of  unequalities.  It  may  be  protected 
with  a  coat  of  gum  arabic  or  of  plain  collodion 
prepared  as  described  on  page  114. 

In  order  to  obtain  prints  in  as  short  a  time 
as  possible,  it  is  necessary  to  use  a  larger  pro- 
portion of  salt  or  chloride  of  ammonium  in  the 


178 


paper  than  for  prints  by  contact.  Ammo- 
nia nitrate  paper  salted,  with  ten  grains  to  the 
ounce  of  chloride  of  ammonium,  and  silvered 
with  a  60  or  70  grain  silver  solution,  can  be 
used  with  advantage.  The  solutions  can  be 
prepared  according  to  the  directions  given  in 
Chapter  XXVII,  the  citric  acid  and  carbonate 
of  soda  being  used  or  omitted  in  the  salting, 
according  to  the  taste  of  the  operator.  Albu- 
men paper,  strongly  salted — that  is,  10  or  12 
grains  to  the  ounce- — will  also  answer. 

The  focus  having  been  taken  beforehand, 
the  sensitive  paper  is  tacked  on  a  board  or 
stretched  on  a  frame,  and  put  in  the  place  oc- 
cupied by  the  focussing  screen.  The  reflector 
is  then  turned,  so  as  to  throw  the  sunlight  on 
the  negative  in  such  a  way  as  to  bring  the 
spark  or  focus  of  the  rays  in  the  middle  of  the 
aperture  of  the  diaphragm.  Gradually  as  the 
sun  moves,  the  reflector  will  have  to  be  moved, 
so  as  to  keep  the  spark  always  in  the  same 
place.  This  requires  to  be  done  about  every 
one  or  two  minutes. 

The  time  of  exposure  is  regulated  by  the 
following  conditions  : 

1st,  The  strength  of  the  light. 

2d,  The  intensity  of  the  negative. 

3d,  The  sensitiveness  of  the  paper. 

4th,  The  proportion  between  the  size  of  the 
negative  and  the  one  of  the  print.  It  is  easy 
to  comprehend  that  the  larger  the  negative 
is,  the  more  luminous  will  be  the  image,  and 


179 


the  larger  the  image  is  the  less  luminous  it 
will  be. 

5th,  The  distance  the  negative  is  from  the 
condensing  lens. — The  further  the  negative 'm 
from  the  condensing  lens,  the  smaller  and  the 
more  luminous  is  the  disc  of  light  thrown  on 
it.  In  order  to  make  prints  rapidly,  it  is  thus 
essential  to  use  a  lens  of  such  a  focus,  that  the 
negative  be  as  far  from  the  condensing  lens  as 
possible,  so  as  to  be  coverd  with  a  small  but 
luminous  disc  of  light. 

The  toning,  fixing,  etc.,  of  the  image  having 
been  fully  described  in  chapter  XXIX,  it  is  un- 
necessary to  repeat  it  here. 

The  dishes  for  toning,  fixing  and  washing, 
can  be  made  of  dry  wood,  and  are  made  water- 
tight by  pouring  a  cement,  composed  of  equal 
parts  of  wax  and  rosin,  in  the  cracks  and  cor- 
ners, and  varnishing  with  shellac  or  copal 
varnish. 


CHAPTER  XXXIII. 

Enlarged  Prints  by  the  Developing  Process. 

The  room  which  is  used  for  the  production 
of  developed  prints  must  be  perfectly  dark, 
and  all  the  precautions  required  in  producing 
.  collodion  pictures  should  be  taken. 

The  solutions  should  be  well  filtered,  and 
everything  kept  in  perfect  cleanliness. 


180 


The  silver  solution  should  be  prepared  with 
as  much  care  as  in  the  collodion  process,  and 
it  should  be  kept  as  much  as  possible  free 
from  organic  matter. 

We  will  describe  here  two  processes,  one 
which  is  adapted  best  to  the  production  of 
plain  prints,  on  ordinary  photographic  paper ; 
another,  which  for  reasons  of  economy  and 
celerity,  will  be  found  more  useful  whenever 
images  have  to  be  made  of  a  larger  size. 

Developing  process  on  photographic  paper.— 
For  this  process,  it  is  necessary  to  have  one 
or  several  dishes,  for  iodizing,  silvering  and 
developing,  a  little  larger  than  the  picture  you 
want  to  print.  The  most  economical  dishes, 
and  the  best  and  cleanest,  are  composed  of  a 
framework  in  which  a  plate  of  glass  is  sealed 
with  a  cement  composed  of  equal  parts  of  rosin 
and  beeswax.  The  sides  of  the  framework 
should  be  about  four  inches  high  and  one  inch 
thick.  In  these  sides  is  a  groove  half  an 
inch  deep  and  a  quarter  of  an  inch  wide.  The 
framework  is  fastened  together  with  screws. 
Join  firstly  three  pieces,  then  slide  the  plate 
of  glass  into  the  groove,  and  screw  on  the 
fourth  pieca  After  that  pour  into  the  groove 
your  melted  cement,  and  finally  varnish  the 
wood  several  times  with  shellac  dissolved  in 
alcohol,  or  with  copal  varnish.  These  dishes 
can  be  used  on  both  sides,  and  are  very  easily 
cleaned.  This  is  done  first  with  a  clean 
sponge,  and  then  the  dish  is  put  with  one  cor- 


181 


ner  into  a  bucket,  and  water  sprinkled  over 
with  a  watering  pot. 

For  fixing,  toning  and  washing,  wooden 
dishes,  well  cemented  and  varnished,  will  • 
answer. 

The  paper  is  floated  one  minute  on  the  fol- 
lowing solution  : 


The  solution  can  also  be  brushed  over  the , 
paper  by  means  of  a  cotton  brush.  The  paper 
being  iodized  is  hung  up  to  dry. 

The  proportion  of  chloride  of  ammonium 
can  be  varied.  When  negatives  are  used, 
which  are  intense  enough  to  give  good  ammo- 
nia nitrate  prints  by  contact,  the  quantity  of 
chloride  of  ammonium  maybe  reduced  to  one 
drachm.  With  very  weak  negatives,  such  as 
are  required  to  make  direct  prints  by  means  of 
the  solar  camera,  it  can  be  increased  to  one 
half  ounce.  The  proportion  given  in  the  for- 
mula is  adapted  for  negatives  of  medium  in- 
tensity, and  will  be  found  generally  useful. 

The  French  and  German  papers  take,  after 
being  iodized,  a  reddish  color,  which  is  due  to 
the  starch  used  as  sizing.  The  English  pa- 
pers, which  are  sized  with  gelatine,  remain 
white. 

The  paper  should  not  be  iodized  longer  than 
a  few  days  before  it  is  used. 


Iodide  of  potassium,. . , 
Chloride  of  ammonium 
Distilled  water  


,  ounce. 
,  k£  ounce. 
40  ounces. 


182 


The  following  is  the  formula  for  the  silver 
solution : 


This  solution  has  first  to  be  saturated  with 
fjdide  of  silver,  if  not,  it  dissolves  the  iodide 
of  silver  from  the  surface  of  the  paper,  and 
nothing  but  a  faint  image  can  be  obtained. 
Two  grains  of  iodide  of  potassium,  dissolved 
in  a  small  quantity  of  water,  will  yield  iodide 
of  silver  enough  to  saturate  the  solution.  The 
solution  being  filtered,  pour  into  it,  a  few 
drops  at  a  time,  a  solution  of  acetate  of  am- 
monia, until  the  precipitate  of  acetate  of  silver 
which  is  formed  ceases  to  be  dissolved  by  agi- 
tation, after  which  filter  again.  The  solution 
of  acetate  of  ammonia  is  made  by  neutralizing 
aqua-ammonia  by  means  of  acetic  acid,  till  the 
smell  of  the  ammonia  has  disappeared,  and 
the  liquid  has  a  faint  acid  reaction  on  litmus 
paper. 

As  a  developer  use  in  cold  weather  a  satur 
ated  solution  of  gallic  acid  in  distilled  or  rain 
water,  and  add  to  it  a  few  drops  of  acetic  acid, 
to  prevent  it  from  decomposing.  During  the 
summer  months,  dilute  it  with  an  equal  bulk 
of  water. 

The  fixing  solution  is  prepared  according  to 
the  following  formula. 


Nitrate  of  silver,. 
Distilled  water, . . 
Acetic  acid,  No.  8S 


1  ounce. 
12  ounces  fluid. 
,  2  ounces. 


Hyposulphite  of  soda, 

Water,  

Bi-carbonate  of  soda, . , 


.16  ounces. 
.  40  ounces. 
.  ounce. 


183 


The  paper  having  been  iodized  and  dried, 
set  the  image  in  focus,  using  to  focus  upon  one 
of  your  dishes  on  the  glass  of  which  has  been 
pasted  a  piece  of  white  paper.  The  focussing, 
as  we  have  seen  already,  should  not  be  done 
with  the  sunlight  reflected  upon  the  negative, 
but  by  diffused  light.  This  being  done,  pour 
the  silver  solution  in  the  glass  dish  and  inl- 
ine rge  the  paper  for  about  five  minutes. 
When  the  one  sized  with  starch  is  used,  it  is 
very  easy  to  see  when  all  the  iodizing  is  trans- 
formed into  iodide  and  chloride  of  silver,  for  the 
reddish  color  disappears,  and  the  paper,  from 
opaque,  becomes  transparent. 

In  order  to  have  pictures  free  from  stains  and 
spots,  the  greatest  cleanliness  is  required.  The 
dishes  have  to  be  well  washed  and  the  solutions 
filtered.  The  silver  solution  has  also  to  be  in 
such  a  quantity  as  to  enable  you  to  pass  the 
paper  through  it  without  pauses,  otherwise 
lines  will  be  produced  similar  to  those  found 
on  collodion  plates,  when  checked  while  dip- 
ping them. 

After  the  paper  has  been  silvered,  pour 
off  the  silver  solution,  and  put  the  dish  in 
its  place  on  the  stand.  Fasten  the  upper  part 
of  it  to  the  stand,  by  means  of  a  string  or  an 
iron  wire,  and  put  a  bottle  and  funnel  under  it 
to  receive  the  silver  solution  which  drains  from 
the  paper.  Then  put  on  the  cover  of  your 
tube,  put  the  diaphragm  in  its  proper  place, 
and  bring  the  reflector  in  such  a  position  that 


184 


the  spark  passes  through  the  center  of  the 
aperture.  The  time  of  exposure  cannot  be 
given,  it  must  be  judged  by  the  appearance 
of  the  paper.  The  more  intense  the  negative 
is,  the  more  it  will  be  necessary  to  see  the 
image  before  developing.  The  more  chloride 
of  ammonium  has  been  used  in  the  first  pre- 
paration, the  stronger  also  the  image  will  have 
to  be  printed.  If  a  weak  negative  was  used 
to  produce  an  image,  on  paper  in  which  little 
chloride  of  ammonium  is  used,  it  will  be  neces- 
sary only  to  see  the  stronger  outlines  which 
will,  in  good  light,  take  only  a  few  seconds. 
Chloride  of  silver  thus  gives  strength  to  the 
image,  but  causes  the  paper  to  be  less  sensi- 
tive. 

It  will  be  necessary,  if  the  spark  changes 
perceptibly  its  place  during  the  exposure  of  the 
sensitive  paper  to  light,  to  bring  it  again  into 
the  center  by  moving  slightly  the  reflector. 

The  next  operation  is  the  development. 
Lay  the  dish  containing  the  impressioned  pa- 
per flat  on  the  table,  and  cover  it  with  the  de- 
veloping solution,  using  to  pour  it  on  a  bottle 
with  a  wide  mouth.  This  requires  to  be  done 
with  some  dexterity,  as  lines  of  irregular  de- 
velopment might  be  produced.  It  will  be 
necessary  in  the  start  to  use  about  eight  or  ten 
ounces  of  the  developer  to  cover  well  a  sheet 
of  photographic  paper,  but  with  a  little  prac- 
tice, the  operator  will  be  enabled  to  do  it  with 
half  this  quantity.    When  the  paper,  by  long 


185 


exposure,  has  partially  dried,  a  larger  quanti- 
ty of  developer  has  to  be  used  than  otherwise, 
as  it  is  difficult  to  cover  it  in  this  case. 

Two  stages  in  the  development  are  noticed: 
the  first  stage,  in  which  the  picture  appears 
with  almost  all  of  its  details,  but  has  a  red 
tint ;  the  second  stage,  in  which  but  very  little 
more  appears,  but  in  which  the  tint  of  the 
picture  from  red  is  changed  to  black.  An 
over  exposed  print  develops  with  great  rapi- 
dity, and  entirely,  before  the  second  stage  is 
reached,  and,  if  the  development  is  carried  to 
that  point,  will  lose  the  purity  of  its  whites. 
An  under  exposed  print  develops  slowly,  and 
becomes  black  before  all  the  half  tones  have 
made  their  appearance. 

The  black  image  obtained  by  full  develop- 
ment to  the  second  stage  changes  little  in  the 
hyposulphite.  The  tint  of  such  an  image  is 
not  as  pleasing  as  the  one  of  a  direct  positive 
print,  properly  toned.  A  much  better  tone 
can  be  obtained  by  exposing  the  paper  a  little 
longer  to  the  light,  developing  it  to  the  red 
stage  and  toning  it  in  the  alkaline  chloride  of 
gold  bath.  Such  prints  are  altered  slightly 
during  the  toning  and  fixing,  so  that  they  will 
have  to  be  developed  a  little  stronger  than  they 
are  intended  to  appear. 

In  warm  weather  the  development  proceeds 
rapidly,  in  cold  weather  it  goes  on  very  slowly. 
It  is  advisable  then  to  keeo  the  developing  so- 
ls 


186 


iution  slightly  warm,  by  letting  it  remain  near 
a  fire. 

It  is  easy  to  be  deceived  by  the  appearance 
of  the  print  during  the  development,  for  by 
artificial  light  it  seems  always  darker  than  by 
day  light. 

When  the  picture  has  arrived  at  the  re- 
quired intensity,  the  development  has  to  be 
stopped.  This  cannot  be  done  by  washing  it,  the 
gallic  acid  and  nitrate  of  silver  remaining  long 
in  the  paper,  and  the  development  continuing 
while  the  proof  is  soaking  in  the  water.  The 
proper  way  is  to  precipitate  the  silver  in  an 
insoluble  state  by  pouring  on  a  solution  of 
common  salt.  The  salt  transforms  the  free 
nitrate  of  silver  into  chloride,  and  the  develop- 
ment is  stopped  instantaneously.  There  is  no 
necessity  of  pouring  out  the  developing  solu- 
tion before  adding  the  salt  water.  The  chlo- 
ride of  silver  thus  formed  can  be  collected  and 
transformed  into  metallic  silver  in  the  ordi- 
nary way. 

The  picture  should  not  be  allowed  to  remain 
in  the  solution  of  salt,  as  the  salt  has  the  power 
of  transforming  into  white  chloride,  the  finely 
divided  silver  which  forms  the  image. 

The  development  being  stopped,  the  print 
is  washed  several  times  in  clean  water  to  re- 
move all  the  gallic  acid,  after  which  it  is  toned, 
fixed  and  washed  in  the  same  way  as  the 
direct  positives.  The  first  washing,  the  toning 
find  the  fixing  should  not  be  done  in  strong  light, 


187 


as  the  purity  of  the  whites  would  be  affected. 
The  fixing  is  done  when  the  yellow  appear- 
ance given  to  the  paper  by  the  iodide  of  silver 
has  disappeared  by  transmitted  light.  The 
hyposulphite  has  then  to  be  washed  out  with 
the  same  care  and  by  the  same  means  as  in 
the  ordinary  printing  process. 

Instead  of  silvering,  exposing  and  develop- 
ing in  a  dish,  the  paper  can  be  pinned  on 
a  board  covered  with  a  sheet  of  blotting  pa- 
per, and  the  solution  brushed  on.  This 
requires  to  be  done  with  some  dexterity,  to 
avoid  marks  of  the  brush  or  cotton.  It  is  also 
advisable,  to  make  the  silver  solution  a  little 
stronger,  using,  for  instance,  nine  or  ten,  in- 
stead of  twelve  ounces  of  water  to  the  ounce 
of  nitrate  of  silver.  The  focus  is  taken  on 
the  paper  itself  before  sensitizing.  After 
sensitizing,  the  paper  is  found  to  have  ex- 
panded considerably,  so  that  it  has  to  be 
stretched  out  again.  The  focus  also  may  have 
to  be  adjusted  again;  the  sensitive  paper 
being  a  little  nearer  the  lens. 

Another  Process. 

The  process  we  are  going  to  describe  now 
is  different  in  two  respects  from  the  foregoing : 
1st,  The  iodide  of  silver,  instead  of  being 
formed  by  floating  the  paper  alternately  upon 
solutions  of  iodide  of  potassium  and  nitrate  of 
silver,  is  formed  by  brushing  on  it  the  double 
iodide  of  potassium  and  silver,  and  decompos- 


188 


ing  the  double  iodide  by  soaking  in  water, 
2d,  The  paper  is  rendered  sensitive  by  means 
of  aceto-nitrate  of  silver  and  gallic  acid,  instead 
of  aceto-nitrate  of  silver  alone. 

Iodizing. — A  solution  of  double  iodide  of 
silver  and  potassium  is  prepared  in  the  follow- 
.  ing  way :  Take  120  grains  iodide  of  potassium  ♦ 
and  120  grains  nitrate  of  silver,  dissolve  each 
of  these  salts  in  ten  ounces  of  distilled  water, 
and  mix  the  solutions  together  in  a  quart  bot- 
tle. The  precipitate  which  is  thrown  down 
is  iodide  of  silver,  and  is  allowed  to  settle, 
when  the  liquid  is  poured  off,  and  the  precipi- 
tate is  washed  several  times  with  distilled 
water,  in  the  manner  described  on  page  55, 
the  washing  with  alcohol,  of  which  there  is 
question  there,  being  dispensed  with.  The 
iodide  of  silver  is  then  put  into  a  measure,  the 
measure  is  filled  up  to  six  ounces  with  distilled 
water,  and  iodide  of  potassium  is  added  to  it 
until  the  whole  of  the  iodide  of  silver  is  dis- 
solved. This  will  take  about  two  and  a  half 
ounces.  The  double  iodide  of  silver  and 
potassium  thus  obtained  has  to  be  filtered 
through  Swedish  paper  into  a  clean  and  dry 
bottle. 

The  paper  is  floated  on  this  solution,  or  the 
solution  is  brushed  over  the  paper  by  means 
of  a  cotton  brush,  such  as  is  used  to  silver  the 
ammonia-nitrate  paper,  after  which  it  is  hung 
up  to  dry.    One  sheet  of  photographic  paper 


189 


will  take  up  four  or  five  drachms  of  the  so- 
lution. ' 

The  next  operation  consists  in  decomposing 
the  double  iodide  of  potassium  and  silver  by 
means  of  water.  We  must  remark  here,  that 
when  to  a  solution  of  this  salt  water  is  added, 
the  iodide  of  silver  will  immediately  precipi- 
tate, for  a  concentrated  solution  of  iodide  of 
potassium  only  has  the  power  to  dissolve  the 
iodide  of  silver.  When  the  paper  prepared 
as  described  above  is  immersed  in  a  tray  of 
water,  the  iodide  of  potassium  will  dissolve 
and  leave  the  iodide  of  silver  in  the  texture  of 
the  paper.  The  paper  should  be  allowed  to 
soak  in  the  water  for  about  half  an  hour,  the 
water  is  then  changed,  and  it  is  left  in  for  half 
an  hour  or  an  hour  longer,  after  which  it  is  hung 
up  to  dry.  Instead  of  the  first  soaking,  it  may 
be  washed  for  five  or  ten  minutes  under  a 
hydrant  or  tap,  in  the  way  prescribed  to 
remove  the  hyposulphite  out  of  prints.  See 
page  157.  When  a  number  of  sheets  of  paper 
have  to  be  washed,  several  may  be  immersed 
at  a  time,  if  abundance  of  water  is  used,  and  if 
frequently  turned  over  and  changed. 

The  paper  prepared  this  way  is  said  to  keep 
any  length  of  time.  It  is  of  a  pale  yellow 
color  and  is  insensitive  to  light 

Sensitizing.— When  required  to  be  used,  it  is 
laid  down  flat,  and  the  back  is  moistened  with 
a  sponge  to  prevent  unequal  expansion  in  the 
subseouent*  operations.     It  is  then  pinned 


X 

190 

or  tacked  on  a  screen.  The  preliminary 
arrangements  to  the  exposure  may  have  been 
made  beforehand,  or  the  paper  which  has  to 
receive  the  image  can  be  used  to  focus  upon. 
The  last  plan  is  more  expeditious. 

The  paper  is  now  ready  to  be  made  sensi- 
tive to  the  light.  For  this,  prepare  the  four 
following  solutions,  which  we  will  call,  Nos.  1, 
2,  3  and  4 


N0»  1 — Nitrate  of  silver,  480  grains. 

Acetic  acid,  No.  8     4  ounces  fluid. 

Distilled  water,  8  ounces  fluid. 

NO.  2— Gallic  acid  1  drachm. 

Alcohol,  h  2  ounces  fluid. 

Acetic  acid,  No.  8,   1  ounce  fluid. 

Distilled  water,  9  ounces  fluid. 

NO.  3— Solution,  No.  1,   1%  ounces  fluid- 

Distilled  water,  10  ounces  fluid, 

NO.  4— Solution,  No.  2,   2  drachms  fluid, 

Distilled  water,  12  ounces  fluid. 


Mix  four  drachms  of  solution  No.  3,  and  the 
same  quantity  of  solution  No.  4  together,  pour 
the  mixture  on  the  paper,  and  with  a  cotton 
brush  spread  it  equally  over  the  surface,  brush- 
ing it  across  the  paper  and  up  and  down. 
This  should  be  well  attended  to,  otherwise  the 
marks  of  the  brush  might  show  after  develop- 
ment. 

When  the  paper  is  well  saturated,  the  ex- 
cess, if  there  is  any,  is  drained  off,  and  the 
paper  is  exposed  to  the  light. 

The  quantities  given  above  are  for  a  whole 
sheet  of  photographic  paper. 

Exposure  to  light — The  paper  prepared  by 


191 


this  method  is  more  sensitive  than  the  one 
described  before.  The  developing  going  on 
already  while  the  light  is  acting,  it  will  be 
necessary  to  see  more  of  the  image  before  the 
final  development  than  when  no  gallic  acid  is 
used  in  the  sensitizing.  With  such  negatives 
as  give  good  prints  by  contact  on  ordinary 
ammonia-nitrate  paper,  the  exposure  will  have 
to  be  continued  until  the  image  is  well  seen  in 
all  the  outlines,  and  the  half  dark  shadows  are 
marked.  With  weak  negatives,  it  should  not 
be  pushed  so  far. 

Development. — The  developing  fluid  is  com- 
posed of  one  part  of  solution  'No.  1,  mixed  with 
six  parts  of  solution  No.  2.  This  mixture  is 
spread  over  the  paper  with  the  same  brush 
which  has  been  used  to  sensitize.  This  should 
be  done  with  dexterity  and  rapidly  to  prevent 
marks  of  the  brush  being  produced.  If  the 
paper  is  of  a  large  size,  or  if  it  has  been  over 
exposed,  it  is  best  to  dilute  the  developing 
fluid  with  an  equal  quantity  of  water.  This  is 
also  to  be  recommended  in  warm  weather.  If 
the  paper,  by  being  exposed  a  long  time,  has 
become  too  dry,  it  is  advisable  to  brush  it  over 
with  the  mixtures,  No.  3  and  No.  4,  before  ap- 
plying No.  1  and  ~No.  2.  The  image  develops 
generally  slower  than  when  the  other  process 
is  used.  When  it  has  fully  appeared,  spread 
over  it  a  solution  of  salt,  which,  in  precipitating 
the  nitrate  of  silver  in  the  state  of  chloride,  will 
stop  the  development. 


192 


Toning,  fixing  and  washing. — The  image  can 
be  toned  in  the  alkaline  gold  bath,  if  any 
toning  is  required.  For  prints  which  have  to 
be  painted,  the  development  can  be  pushed  to 
the  second  stage,  when  no  toning  will  be  neces- 
sary. The  fixing  is  done  in  the  same  solution 
which  has  been  prescribed  for  the  other  pro- 
cess. 

It  is  perhaps  well  to  repeat  here  that  before 
toning  or  fixing,  the  gallic  acid  should  be 
washed  out,  to  prevent  decomposition  of  the 
toning  or  discoloration  of  the  fixing  solution. 

To  work  successfully  this  process,  every 
thing  should  be  kept  with  the  greatest  clean- 
liness. The  measuring  glass,  in  which  solutions 
Nbs.  1,  2,  3  and  4  are  mixed,  should  be  washed 
out  after  each  operation,  and  care  should  be 
taken  to  remove  the  black  deposit  which  forms 
in  it.  The  mixture  of  gallic  acid  and  nitrate 
of  silver  will  keep  for  hours  in  the  dark,-  but 
if  the  slightest  trace  of  this  deposit  was  present, 
it  would  discolor  in  a  few  minutes.  The  same 
cause  necessitates  the  use  of  a  new  brush  for 
each  picture. 

The  great  sensitiveness  of  this  process  will 
oblige  the  operator  to  use  the  utmost  caution 
to  shield  his  sensitive  paper  from  the  influence 
of  light.  Every  part  of  the  negative,  which  is 
not  to  be  printed,  should  be  covered  with  a 
mat,  and  the  diaphragm  should  be  as  small  as 
possible,  so  as  to  admit  no  unnecessary  light 


I 


193 


in  the  dark  room.  The  artificial  light  should 
also  be  as  feeble  as  possible. 

0 


CHAPTER  XXXIV. 

Preserved  and  Drf  Collodion  Processes. 

If  a  sensitized  collodion  plate  is  kept  for 
some  time,  the  solution  of  nitrate  of  silver, 
concentrating  by  evaporation,  will  dissolve 
the  iodide  of  silver,  and  afterwards  crystallize, 
thus  destroying  the  film.  The  collodionized 
and  sensitized  plate  should  thus  be  exposed 
and  developed  immediately  after  its  prepara- 
tion, so  that  the  landscape  photographer  is 
obliged  to  have  on  the  spot,  where  he  wishes 
to  take  a  view,  all  the  paraphernalia  belong- 
ing to  the  wet  process,  including  a  dark 
closet  or  tent,  in  which  to  sensitize  and  de- 
velop the  plate. 

The  great  disadvantage  of  this  process  for 
out-door  work,  principally  when  the  site  for 
operating  is  of  difficult  access,  has  naturally 
induced  researches  as  to  the  practicability  of 
preserving  the  collodion  film.  It  was  pro- 
posed at  first,  by  Messrs.  Spiller  and  Crookes, 
to  use,  mixed  with  the  silver  bath,  some  salt  pos- 
sessing strong  deliquescent  properties,  so  that 
the  film,  after  sensitizing,  was  kept  moist. 
This  process,  however,  gave  but  imperfect 
results.  Mr.  G.  -Shadbolt  then  proposed  to 
ir 


194 


cover  the  plate,  after  sensitizing,  with  diluted 
honey.  This  was  done  immediately  after 
withdrawing  the  plate  from  the  bath;  or 
the  plate  was  washed  to  remove  the  larger 
quantity  of  nitrate  of  silver,  before  the  honey 
was  applied.  Mr.  Llewellyn  substituted  ox- 
ymel,  in  diluted  solution,  to  honey.  Oxy- 
mel  is  a  mixture  of  honey  and  acetic  acid. 
Both  processes  were,  however,  abandoned,, 
on  account  of  the  difficulty  of  keeping  the 
plates  longer  than  a  day,  and  the  tendency  to 
fogging,  caused  by  the  action  of  the  honey 
on  the  free  nitrate  of  silver. 

Experiments  were  then  made  to  use  the 
collodion  plate  in  a  dry  state.  It  was  dis- 
covered, that  under  certain  conditions,  a  plate 
which  had  been  washed  and  then  driedy  was 
still  sensitive ;  and,  that  after  a  comparatively 
long  exposure,  such  a  plate  yielded  an  image 
by  development  with  gallic  orpyrogallic  acid, 
and  nitrate  of  silver.  In  this  process  success 
seems  to  depend  on  the  molecular  state  of 
the  collodion,  and  on  the  presence  in  it  of  cer- 
tain kinds  of  organic  matter,  which  produce 
a  sensitive  compound  with  nitrate  of  silver. 
Collodion  prepared  with  a  certain  variety  of 
pyroxyline,  and  allowed  to  ripen,  seems  gen- 
erally to  possess  these  qualities.  Also,  collo- 
dion which  has  been  partly  decomposed,  or 
to  which  a  small  quantity  of  resin  has  been 
added. 

The  theory  of  the  dry  collodion  process  is 


195 


a  problem  which  we  will  not  here  attempt  to 
solve*  We  will  merely  dwell  somewhat  on 
the  two  conditions  necessarv  to  success,  which 
we  have  just  mentioned.  First,  The  collo- 
dion film,  instead  of  being  hard  and  horny, 
should  be  soft  and  porous.  The  reason  for 
this  is  easily  understood.  For  if  the  film, 
after  washing  and  drying,  presents  a  glassy 
or  polished  surface,  impenetrable  to  liquids,  it 
will  be  impossible  to  deposit  reduced  silver  in 
its  texture  during  the  process  of  development. 
Second,  The  collodion  should  also  contaui 
matter  capable  of  forming  a  sensitive  sub- 
stance by  combination  with  silver ;  for  it  is  a 
well  known  fact,  that  iodide  of  silver,  perfectly 
washed,  is  quite  insensitive  to  light ;  and  that 
pure  pyroxyline,  free  from  the  species  of  or- 
ganic matter  alluded  to,  is  entirely  unaftected 
by  the  salts  of  silver.  But  iodide  of  silver, 
in  the  presence  of  nitrate  of  silver,  or  of  an 
organic  silver  compound,  is  a  sensitive  sub- 
stance ;  so  that  a  plate  imperfectly  washed,  or 
one  prepared  with  the  species  of  collodion 
spoken  of  above,  is  still  in  a  sensitive  con- 
dition. But  imperfectly  washed  plates  keep 
but  a  very  short  time,  so  that  this  means  of 
preserving  the  sensitiveness  is  unavailable. 

The  collodion  for  the  dry  process  should  be 
prepared  with  pyroxyline  made  at  a  high 
temperature,  and  with  excess  of  sulphuric 
acid,  as  recommended  by  Harclwich.  Such 
collodion  contains  the  organic  principle  neces- 


196 

sary  in  the  dry  processes  ;  and  after  it  has  been 
kept  some  time,  or  when  mixed  with  about 
one-fourth  of  old  .decomposed  collodion,  the 
quantity  of  this  principle  is  increased,  and 
the  collodion  becomes  sufficiently  porous. 

Although,  under  the  conditions  we  have 
spoken  of,  that  is,  a  porous  film,  and  the  pres- 
ence of  a  sensitive  organic  silver  compound, 
negatives  can  be  obtained  on  plates  merely 
washed  and  dried,  success  is  more  certain, 
when  the  plate,  after  washing,  is  coated  with 
some  organic  substance,  like  albumen,  gela- 
tine, gum  arabic,  tannin,  etc.  The  function 
of  these  substances  seems  to  be :  First,  To 
fill  up  the  pores  of  the  collodion  film,  so  that 
it  be  penetrable  by  liquid  when  dry ;  and, 
second,  To  facilitate  the  deposit  of  silver 
during  the  development. 

We  will  describe  now  some  of  the  dry  pro- 
cesses most  in  use  :  1st,  The  tannin  process; 
2d,  The  tannin  and  honey  process ;  3d,  The 
colloclio-albumen  process ;  4th,  The  Fother- 
gill  albumen  process. 


CHAPTER  XXXV. 

The  Tannin  Process. 

In  the  tannin  process,  as  described  by 
Major  Russell,  the  plate  is  first  coated  with  a 
solution  of  gelatine,  then  collodionized,  ex- 
ciled  and  washed,  and  finally  coated  with  a 


197 


solution  of  tannin,  and  dried.  In  the  case, 
however,  when  the  collodion  used  is  well 
adapted  to  the  dry  process ;  that  is,  when  it 
contains  the  organic  principle  before  alluded 
to,  and  gives  a  film  which  is  porous  when  dry, 
the  coating  with  gelatine  can  be  dispensed 
with.  According  to  Major  Russell,  the  pre- 
vious coating  with  this  substance  makes  suc- 
cess independent  of  the  state  of  the  collodion, 
and  causes  the  film  to  adhere  better  to  the 
glass. 

We  will  divide  the  description  of  the  tan- 
nin process  into  seven  parts  : 

1 .  Cleaning  of  the  glass. 

2.  Collodionizing,  exciting  and  washing. 

3.  Coating  with  tannin. 

4.  Exposure  in  the  camera. 

5.  Developing. 

6.  Fixing." 

7.  Drying  and  varnishing. 

Major  Russell  recommends  that  the  edges 
of  the  glass  should  be  ground,  and  that  the 
grinding  should  extend  a  little  way  on  the 
surface  when  the  previous  coating  with  gela- 
tine is  dispensed  with.  This  operation  he 
describes  as  follows :  The  neatest  way  to 
grind  the  glass  in  this  manner,  is  with  a  piece 
of  stout  sheet  copper,  along  the  middle  of 
which  has  been  soldered  a  narrow  strip  of  the 
same  metal,  about  one-sixteenth  of  an  inch 
thick ;  on  the  other  side  a  piece  of  wood  may 
be  screwed,  to  give  a  better  hold.    Mix  some 


198 


silver  sand,  brown  sugar  and  water,  and  with 
a  little  of  this  mixture  in  the  angle,  rub  the 
thick  copper  against  the  edge  of  the  glass,  at 
the  same  time  grinding  the  upper  surface  with 
the  lower  edge  of  the  thin  strip.  The  plate 
is  held  down  with  the  left  hand  on  a  piece  of 
wood,  or  other  convenient  place,  with  the 
edge  that  is  being  ground  slightly  projecting ; 
if  it  project  far,  the  glass  may  be  broken. 
The  edge  and  a  narrow  strip  on  the  surface 
can  in  this  way  be  ground  without  wanding 
off  the  angle.  The  use  of  the  sugar  is  to 
render  the  dirt  more  easy  to  wrash  off.  If  the 
plates  are  to  be  coated  with  gelatine,  it  is 
better  to  grind  only  the  edges,  for  the  ground 
glass  impedes  the  flow  of  the  gelatine,  and  is 
not  in  this  case  required  to  make  the  film 
adhere. 

The  cleaning  of  the  glass  should  be  done 
with  the  greatest  care,  as  any  greasiness 
would  repel  the  gelatine  with  which  they  have 
to  be  coated. 


The  following  is  the  formula  of  the  gela- 
tine solution  : 


Put  the  gelatine  with  the  wTater  in  a  porce- 
lain evaporating  dish,  leave  it  until  the  gela- 
tine has  softened,  and  warm  to  effect  its  solu- 


Coating  with  Gelatine. 


Cox  sparkling  patent  gelatine 

Distilled  water,  k  

Acetic  acid,  No.  8,  

Alcohol,  c  


60  gains. 
12  ounces. 
3  drachms, 
2  ounces. 


199 


tion.    Then  add  the  alcohol  and  the  acetic 

acid,  and  filter  through  a  tuft  of  cotton. 

The  coating  with  gelatine  should  be  done 
In  a  warm  room,  free  from  dust,  and  the  so- 
lution itself  should  be  warm  enough  to  flow 
easily.  It  can  be  poured  on  to  the  glass  out  of 
a  wide-mouthed  bottle  in  the  same  manner  as 
collodion,  or  the  plate  can  be  put  on  a  level- 
ing stand  and  the  solution  poured  on  it,  using 
a  "glass  rod  bent  at  one  end,  to  spread  it  over 
the  surface,  In  either  case  the  excess  is  re- 
turned to  the  funnel  to  be  filtered.  The  use 
of  the  india-rubber  pneumatic  plate-holder  is 
much  to  be  recommended,  as  it  will  avoid  the 
handling  of  the  glass  with  the  fingers. 

The  plate  being  coated  with  the  gelatine 
solution,  is  set  to  drain  on  a  sheet  of  blotting 
paper. 

Care  should  be  taken  to  have  no  gelatine 
on  the  back  of  the  plate,  for  it  would  certainly 
spoil  the  nitrate  of  silver  bath. 

Gelatinized  plates  will  remain  good  any 
length  of  time  if  kept  perfectly  dry. 

The  collodion  should  be  allowed  to  dry 
longer  than  in  the  wet  process,  before  dipping, 
so  that  the  film  adheres  well  to  the  plate. 
The  plate  should  also  be  kept  longer  in  the 
silver  solution,  so  as  to  ensure  the  transfor- 
mation of  the  iodide  and  bromide  in  the  col- 
lodion, in  iodide  and  bromide  of  silver. 

COLLODIONIZING,    EXCITING  AND  WASHING*. 

With  the  previous  coating  with  gelatine, 


200 


almost  any  good  negative  collodion  can  be 
used.  If  you  want  to  prepare  it  expressly 
for  the  purpose,  use  it  according  to  the  follow- 
ing formula : 

Iodide  of  ammonium*.  24  grains. 

Iodide  of  cadmium,     8  grains. 

Bromide  of  cadmium,  20  gra  na. 

Negative  pyrosyline,.  „   .59  to  65  grains. 

Alcohol,  4  ounces. 

Ether,  4 . .  4  ounces. 

When  the  plate  has  not  been  coated  with 
gelatine,  it  will  be  necessary  to  use  a  collo- 
dion, giving  a  short  and  powdery  film.  The 
one  prepared  according  to  the  following  direc- 
tions, will  answer  the  purpose :  To  four 
ounces  of  alcohol  add  ten  grains  of  bromide 
of  ammonium,  dissolved  in  a  small  quantity 
of  water,  and  mix  with  four  ounces  of  ether. 
Add  then  thirty-two  grains  of  iodide  of  am- 
monium, and.  eight  grains  of  bromide  of  cad- 
mium, and  shake  until  dissolved.  If  the 
liquid  be  opalescent,  let  it  become  clear  by  set- 
tling, and  to  the  clear  part  add  from  fifty  to 
sixty-five  grains  of  negative  pyroxyline,  made 
at  a  high  temperature. 

This  collodion  may  give  a  suitable  film  im- 
mediately after  its  preparation,  but  if  it  does 
not,  it  will  have  the  required  qualities  after 
being  kept  a  short  time. 

The  silver  solution  is  prepared  as  follows : 


Nitrate  of  silver,   1  ounce. 

Distilled  w.4  r,   12  ounces. 

Iodide  of  potassium,   &  grains. 

Acetic  acid,  .No.  8,   4  drops* 


The  plates  are  to  be  coated  with  collodion. 


201 

sensitized  and  washed.  The  col- 
lodion should  be  allowed  to  dry 
longer  than  in  the  wet  process, 
before  clipping,  so  that  the  film 
adheres  well  to  the  plate.  The 
plate  should  also  be  left  longer 
in  the  silver  solution,  so  as  to 
insure  the  transformation  of 
all  the  iodide  and  bromide  in 
the  collodion,  in  iodide  and  bromide  of 
silver.  If  the  common  water  which  is 
on  hand,  is  pure  enough  not  to  give  a  pre- 
cipitate with  nitrate  of  silver,  it  can  be  used 
for  all  the  washings ;  if  not,  distilled  water 
should  be  used  at  first.  The  washing  can  be 
done  by  means  of  the  washing  bottle,  (see 
annexed  figure,)  or  under  a  tap,  or  in  vertical 
or  horizontal  baths. 

A  very  expeditious  way  is  the  following : 
Fill  two  vertical  baths  with  distilled  water, 
and  two  or  three  porcelain  dishes,  one  of 
which  should  be  large,  with  common  water, 
and  place  all  near  the  silver  bath.  Coat  a 
plate  with  collodion  and  sensitize  it  in  the 
ordinary  way,  only  leaving  it  a  little  longer 
in  the  silver  solution  than  in  the  wet  process. 
When  it  is  about  ready,  collodionize  another 
plate  and  lay  it  down  on  the  mouth  of  a  bot- 
tle. Now  take  out  the  first  plate,  drain  it, 
and  put  it  in  the  first  washing  bath  ;  then 
sensitize  your  second  plate.  If  your  bath  is 
large  enough  to  hold  two  plates,  you  will  find 


202 


it  more  convenient  to  clip  the  second  before 
taking  out  the  first.  Wait  now  till  the  sec- 
ond is  nearly  ready,  when  yon  put  the  first  in 
the  second  bath,  coat  a  third  one,  put  the 
second  in  the  first  bath  and  dip  the  third. 
Proceed  in  this  way  until  all  your  plates  are 
done,  removing  them  from  one  bath  or  dish  to 
the  other,  and  leaving  them  all  in  the  last  one, 
which  should  be  of  large  size.  While  the 
plates  are  in  the  washing  baths  or  dishes,  they 
should  be  moved  up  and  down,  to  facilitate 
the  washing.  The  flat  dishes  or  trays  should 
be  kept  covered  to  avoid  light  and  dust.  The 
plates  are  left  in  the  last  dish  for  half  an 
hour  or  an  hour,  as  it  is  very  important  that 
all  the  nitrate  of  silver  be  removed.  They 
are  then  ready  to  be  coated  with  tannin. 

Coating  With  Tannin. 

Dissolve  four  drachms  of  tannin  in  twelve 
ounces  of  distilled  water,  filter  the  solution 
till  it  is  clear,  and  add  one  ounce  of  alcohol. 

The  plate  having  been  washed  and  drained 
for  a  minute  or  two,  the  tannin  solution  is 
poured  on  it  and  moved  back  and  forth,  till 
an  even  coating  is  obtained,  when  it  is 
poured  off.  The  same  thing  is  then  done  with 
a  fresh  quantity.  The  tannin  solution  used 
for  the  first  coating  may  be  used  over  and 
over  again,  and  the  draining  of  the  second 
added  to  it ;  but  for  the  second  coating,  fresh 
solution  has  always  to  be  used. 


203 


Figure  2. 


The  plate  being  coated  is  set  to  drain  and 
dry  on  blotting  paper,  or  on  a  draining  stand. 
(See  figure  2.) 

Some  dry  plate  workers  wash  the  plate 
again  at  this  period  of  the  operation,  but  we 
have  found  that  the  development  did  not  pro- 
ceed so  well  when  this  was  done. 

It  is  almost  useless  to  say  that  all  these 
operations  must  be  done  at  night  or  in  a  dark 
room.  It  is  even  necessary  to  use  a  very 
feeble  artificial  light,  as  the  plates  would 
otherwise  be  acted  upon,  they  being  exposed 
to  its  influence  during  a  long  time. 

The  drying  should  not  be  done  by  direct 
application  of  heat,  but  rather  spontaneously 
in  a  room  warmed  at  a  moderate  temperature. 

If  the  plates  have  not  been  coated  with 
gelatine,  dip  a  little  brush  in  any  quick  dry- 


2Q4 

ing  varnish,  and  run  it  round  the  edge  of  the 
film. 

The  plates  should  be  kept  in  a  grooved  box, 
with  a  well  fitting  cover.  If  well  washed, 
they  will  keep  their  sensitiveness  for  one 
month,  or  perhaps  longer.  It  is  safest,  how- 
ever, to  put  as  little  time  between  the  prepar- 
ation and  development  as  possible.  The  use 
of  a  changing  box,  to  change  the  plate  in  the 
open  air  from  the  plate-holder,  and  vice  versa, 
is  recommended. 


(Figure  3.) 

The  accompanying  cut  represents  one  of 
these  boxes.  It  is  an  ordinary  grooved  box, 
of  which  the  cover,  F  G,  has  an  opening  0, 
large  enough  to  slide  a  plate  through.  This 
opening,  is  kept  shut  to  prevent  the  admittance 


of  the  light  by  means  of  the  spring  R.  The 
cover  slides  right  and  left,  and  can  be  set  so  that 
the  opening  0  is  over  any  one  of  the  grooves 
in  the  box. 

The  plate-holder 
is  represented  in 
figure  4.  0  is  an 
opening  to  slide  the 
plate  through.  The 
back,  P,  is  pushed 
out  by  means  of 
springs,  and  when 
in  that  state  the 
slide  0  is  open,  but 
if  P  be  pushed  back 
and  T  turned,  the 
slide  0  is  shut.— 
Now  to  change  a 
plate  from  the 
plate-box  to  the 
holder  slide  this  on 

Figure  4.  the  part  I,  J,  M,  N 

of  the  cover,  loosen  the  back  P,  pull  the 
knob  R,  and  turn  the  box  upside  down, 
when  the  plate  will  fall  in  the  holder,  and 
the  back  P  is  pushed  down  to  secure  it. 
To  change  the  plate  from  the  holder  to  the 
box,  slide  the  holder  on  the  cover,  loosen  the 
back  and  pull  back  the  knob. 

Some  difference  will  be  found  in  the  sensi- 
tiveness of  the  plates.  The  principal  causes 
of  insensitiveness  are  the  use  of  a  collodion 


206 

containing  no  bromide,  or  of  too  old  a  sam- 
ple, or  of  a  bath  containing  much  more  acid 
than  is  required  to  make  a  bright  picture. 

Exposure  in  the  Camera. 

The  time  of  exposure  will  range  from  four 
to  ten  times  as  much  as  for  wet  collodion. 

Developing. 

If  the  exact  time  of  exposure  could  be  al- 
ways insured,  it  would  be  easy  to  give  a  form- 
ula for  a  developing  solution,  which  would 
always  answer.  In  the  dry  processes  this  is 
impossible,  as  the  time  of  exposure  must  al- 
ways be  more  or  less  uncertain,  unless  each 
plate  is  immediately  developed,  and  so  the 
proper  time  for  exposure  be  ascertained  for 
the  next.  We  can  thus  only  give  general 
rules,  which,  to  produce  the  best  results,  must 
be  slightly  varied  in  almost  every  case.  The 
following  formula  will  be  found  to  give  devel- 
oping fluids  suitable  for  this  purpose: 


No.  1. — Pyrogallic  acid  26  grains. 

Strong  Alchohol  ,  ,  1  ounce. 

No.  2. — Nitrate  of  Silver   10  grains. 

Citric  acid..  «  20  grains. 

Distilled  water   1  ounce. 


For  a  stereoscopic  plate,  put  one  drop  of 
No.  1  in  two  or  three  drachms  of  distilled  wa- 
ter and  filter  into  a  small  glass  measure. 
While  this  is  being  done,  dip  the  exposed 
plate  into  a  bath  or  dish  of  distilled  water, 
and  after  a  fewT  seconds  immersion,  lift  it  out, 
allow  it  to  drain  and  wipe  the  back  dry.  Lay 
l 


207 


it  then  oil  a  levelling  stand,  and  having  mixed 
one  drop  of  No.  2  to  the  diluted  No.  1,  which 
has  been  filtered,  pour  the  mixture  on  the  end 
of  the  plate  and  incline  it  so  as  to  cause  it  to 
flow  towards  the  other  end  and  back  in  the 
glass.  Repeat  this  several  times,  examining 
the  plate  by  transmitted  light,  and  If  nothing 
appear  in  three  or  four  minutes  add  one  drop 
more  of  pyrogallic.  If,  on  the  contrary,  the 
image  appears  quickly  and  is  full  of  detail, 
but  looks  flat  from  want  of  contrast,  add  more 
silver.  It  may  happen,  also,  that  from  great 
over  exposure  the  film  begins  to  redden  imme- 
diately ail  over,  showing  the  image  but  faintly ; 
if  so  pour  off  the  developer  and  replace  with 
a  few  drops  of  No.  2  diluted,  when  the  py- 
rogallic acid  left  in  the  film  will  be  quite  suffi- 
cient to  complete  the  development.  If  the 
image  shows  about  the  right  contrast  and  the 
middle  tints  begin  to  appear  at  the  proper  time, 
the  No.  1  and  No.  2  may  be  added  together, 
and  if  too  much  of  either  has  inadvertently 
been  added,  the  developer  is  poured  off  and 
replaced  by  a  fresh  one  in  the  proper  propor- 
tions. Should  the  solution  get  turbid,  reject 
and  make  a  fresh  one. 

When  no  previous  coating  of  gelatine  has 
been  used,  the  collodion  will  sometimes,  on 
being  wetted,  expand  strongly,  so  as  to  be 
forced  up  into  ridges,  but  it  will  generally 
contract  again  in  ten  or  fifteen  minutes.  The 


208 


development  must  not  be  begun  before  this 
contraction  takes  place. 

The  development  being  completed,  wash 
until  the  oily  appearance  is  removed.  The 
film,  when  the  plate  is  coated  with  gelatine,  is 
so  strong  that  it  cannot  be  injured  by  a  heavy 
stream  of  water. 

Fixing. 

Cyanide  should  not  be  used  for  fixing,  as 
any  alkaline  liquid  will  losen  the  film.  The 
strength  of  the  hyposulphite  is  of  little  conse- 
quence. The  proportion  we  have  given  for 
wet  collodium,  six  ounces  to  a  pint,  will  an- 
swer. The  film  will  sometimes  become  loos- 
ened in  the  first  washing.  When  this  hap- 
pens, wash  with  a  small  quantity  of  water, 
changing  often.  The  film,  if  not  on  gelatine, 
may  crack  or  split  off  on  drying.  It  is  then 
the  best  to  cover  it  after  draining  with  a  thin 
solution  of  gum  arabic. 

Drying  and  Varnishing. 

The  plates  are  set  to  dry  on  blotting  paper, 
and  when  dry  are  coated  with  any  of  the  ordi- 
nary varnishes  used  for  negatives. 


CHAPTER  XXXVI. 

The  Tannin  and  Honey  Process. 

By  using  as  a  preservative  a  mixture  of  ]  5 
grains  of  tannic  acid  15  grains  of  honey  to 
the  ounce  of  water,  greater  sensitiveness  is 


209 


said  to  be  obtained  than  by  the  use  of  tannin 
alone.  Mr.  England,  who  proposed  this  modi- 
fication of  the  tannin  process,  and  who  prac- 
tices it  successfully,  gives  the  following  for- 
mula : 

Plain  Collodion. 

Alcohol         .„  3  parts. 

Ether   ,  ,  5  parts. 

Pyroxyline,  sufficient  to  give  a  tolerably  thick  film. 

Iodizing  Solution. 

Plain  eollodion.  2J^  ounces  fluid. 

Bromide  of  cadmium  40  grains, 

lodideof  ammonium  30  grains. 

Iodised  Collodion. 

Plain  collodion  3  ounces  fluid. 

Iodizing  solution  * ,   1  ounce  fluid. 

Sensitize  in  a  40-grain  neutral  bath  and 
wash  in  a  bath  or  tray  with  distilled  water, 
slightly  acidulated  with  acetic  acid.  Give  it  a 
final  washing  under  a  tap.  Then  coat  with 
the  solution  of  tannin  and  honey,  fifteen  grains 
to  the  ounce  of  each,  and  set  to  dry  on  blot- 
ting paper.  If  properly  prepared  and  stored 
away  these  plates  will  keep  ten  months.  To 
prevent  the  film  from  leaving  the  glass  pass  a 
sable  pencil,  previously  clipped  in  a  solution 
of  white  wax  and  benzine,  round  the  edge  of 
the  plate,  to  the  extent,  say,  of  one-eighth  of 
an  inch. 

Before  developing,  the  plate  is  left  for  about 
one  minute  in  a  bath  prepared  with  10  grains 
of  nitrate  of  silver  and  5  drops  pf  acetic  acid 
to  the  ounce  of  water.  By  adopting  this  plan 
the  action  of  the  developer  is  almost  as  rapid 

18 


210 

as  in  the  wet  process.  Develop  afterwards 
with  the  pyrogallic  acid  solution  as  usual. 

The  method  of  development  recommended 
by  Major  Russell,  and  described  in  the  pre- 
ceding chapter,  can  also  be  adopted. 


CHAPTER  XXXVII. 

The  Collodio- Albumen  Process. 

In  the  Collodio- Albumen  Process  success  is 
less  dependant  on  the  presence  of  organic 
matter  in  the  Collodion  than  in  any  other  dry 
process  used.  The  reason  for  this  is  that  the 
film  of  iodized  albumen,  with  which  the 
washed  plate  is  covered,  is  itself  transformed 
into  a  sensitive  substance  similar  to  the  one 
found  on  the  ordinary  albumen  plates.  In 
fact  Faupenot's  process  is  in  all  respects  the 
same  as  the  albumen  process  first  practiced  by 
Mepe  de  St.  Victor,  with  the  exception  that 
the  iodized  albumen,  instead  of  being  directly 
used  as  a  coating  on  glass,  is  . used  on  a  collo- 
dionized,  sensitized  and  washed  plate. 

As  far  as  sensitiveness  and  success  is  con- 
cerned, the  collodio-albumen  process,  although 
more  complicated,  is  superior  to  the  plain  al- 
bumen process.  The  only  drawback  is  the 
want  of  adhesiveness  of  the  film,  producing  a 
great  tendency  to  blistering  during  the  devel- 
opment. This  can  be  remedied  by  using  old 
and  decomposed  collodion,  or  collodion  made 


211 


with  a  sample  of  pyroxyline,  giving  a  soft  and 
porous  film. 

The  operations  to  be  performed  can  be 
divided  as  follows : 

1.  Formation  of  the  sensitive  collodion  film. 

2.  Formation  of  the  sensitive  albumen  film. 

3.  Exposure. 

4.  Development  and  fixing. 

Formation  of  the  Sensitive  Collodion  Film. 

The  collodion,  as  we  have  already  noticed, 
should  give  a  short  and  powdery  film.  If 
prepared  expressly  for  the  purpose,  the  follow- 
ing formula  may  be  adopted  : 


Sulphuric  Ether  

Alcohol  

Pyroxyline...  

Iodide  of  Ammonium... 
Bromide  of  Ammonium 


8  ounces,  fluid. 
8  ounces,  fluid. 
100  grains. 
80  grains. 
40  grains.  , 


The  pyroxyline  should  be  of  the  variety 

producing  the  qualities  already  spoken  of,  and 

the  collodion  should  be  allowed  to  stand  for  one 

or  two  months,  so  that  the  alkaline  iodide  and 

bromide,  by  their  action  on  the  dissolved  cotton, 

improve  the  adhesive  qualities  of  the  collodion. 

The  plate  is  coated,  sensitized,  and  washed  in 

the  ordinary  way,  after  which  it  is  drained 

previous  to  coating  with  the  albumen. 

i 

Formation  of  the  Sensitive  Albumen  Film. 

The  albumen  solution  is  prepared  according 
to  the  following  formula: 


212 


Albumen  from  fresh  Eggs 

White  Sugar  

Distilled  Water  

Cone.  Ammonia  

Iodide  of  Ammonium  

Bromide  of  Ammonium  


10  drops. 
10  grains. 
5  grains. 


0  ounces,  fluid* 
J  ounce. 

1  ounce,  fluid. 


Beat  to  a  froth  and  allow  to  subside. 


The  washed  and  drained  plate  is  covered 
with  the  albumen  solution  and  drained  for 
half  a  minute.  It  is  then  covered  with  a 
fresh  portion,  and  set  to  drain  and  dry  on 
blotting  paper,  or  on  a  draining  stand.  The 
second  portion  used  on  the  first  plate  can  be 
used  to  coat  the  second,  and  that  of  the  second 
can  be  used  for  the  third.  It  should  never  be 
returned  to  the  stock  bottle.  The  dried  plates 
should  be  put  in  a  dark  box  for  future  use  and 
can  be  kept  a  great  length  of  time. 

One  or  two  clays  before  the  plates  have  to 
be  exposed,  they  are  dipped  into  a  silver 
solution  prepared  as  follows : 

Nitrate  Of  Silver   1  ounce. 

Distilled  Water   10  ounces. 

Alcohol   2  ounces. 

Acetic-  Acid  No.  8   2  ounces. 

An  old  collodion  silver-bath,  charged  with 
alcohol,  to  which  the  required  quantity  of 
acetic  acid  is  added,  answers  the  purpose  very 
well.  The  addition  of  alcohol  to  this  silver 
solution  decreases  its  tendency  to  discoloration 
produced  by  the  action  of  the  albumen.  If 
it  should  discolor,  nevertheless,  it  should  be 
shaken  with  freshly  precipitated  and  washed 
chloride  of  silver,  which  will  absorb  the  organic 


213 


matter  producing  the  discoloration.  The  plates 
should  be  perfectly  dry  before  dipping,  in  order 
to  avoid  blistering.  They  should  be  left  in  the 
bath  about  one  minute,  after  which  they  are 
washed  in  two  or  three  dishes  of  water,  and 
set  to  dry. 

Exposure. 

The  collodio-albumen  plates,  like  those  pre- 
pared with  tannin,  require  a  long  exposure. 
Much,  however,  depends  upon  the  collodion, 
new  collodion  being  a  great  deal  more  sensitive 
than  old  collodion,  but  its  use  has  to  be  avoided 
on  account  of  the  tendency  to  blistering. 

Development  and  Fixing. 

The  development  is  done  with  pyrogallic 
acid  and  nitrate  of  silver.  The  process  of 
development  given  by  Major  Russell,  and 
described  under  head  of  the  tannin  process,  is, 
in  all  cases,  the  safest.  The  fixing  and  wash- 
ing need  not  be  dwelt  upon,  these  being  the 
same  as  in  all  other  dry  processes. 


CHAPTER  XXXVIII. 

On  Kapid  Dry  Collodion  Plates. 

One  of  the  great  drawbacks  to  the  dry  col- 
lodion process  is  the  long  exposure  required. 
By  various  means,  however,  the  sensitiveness 
of  the  plates  can  be  greatly  increased;  but,  in 


214 


measure,  as  the  sensitiveness  becomes  greater, 
the  difficulties  of  the  development  and  the 
tendency  to  fogginess  increase  also.  Mr. 
Thomas  Sutton  claims  that  in  using  a  bromo. 
iodized  collodion,  containing  iodine  and  bro- 
mine in  equal  atoms  (126  of  iodine  to  78  of 
bromine,)  and  using  gum  arable  instead  of 
tannin,  dry  plates  can  be  made  as  sensitive  as 
wet  plates.  In  the  hands  of  many  good  photo- 
graphers, who  have  experimented  with  this 
process,  great  increase  of  sensitiveness  has  not 
been  observed. 

Dr.  Draper  recommends  that  the  tannin 
plates  should  be  dipped  in  hot  water,  and 
developed  while  yet  warm.  By  this  means, 
the  plate  can  be  developed  with  a  much 
shorter  exposure.  Doubtless,  the  same  effect 
is  produced  on  plates  prepared  by  other  dry 
processes. 

At  the  suggestion  of  Mr.  Henry  Anthony, 
Mr.  Borda,  from  Philadelphia,  exposed  the 
tannin  plate,  before  using  it,  to  the  action  of 
ammonia  gas,  and  in  this  way  obtained  a  great 
increase  of  sensitiveness.  Mr.  Seahy  after- 
wards found  that,  after  a  short  exposure,  a  solu- 
tion of  ammonia  developed  an  image  on  a  tan- 
nin plate,  which  could  afterwards  be  strength- 
ened up  with  pyrogallic  acid  and  nitrate  of 
silver  to  any  extent.  This  observation  of 
Mr.  Seahy  led  to  what  is  called  alkaline 
development.  The  exposed  tannin  plate,  after 
having  been  wetted  with  distilled  water,  is 


•315 


submitted  to  the  action  of  a  dilute  solution 
of  ammonia,  carbonate  of  ammonia,  or  car- 
bonate of  soda.  If  the  exposure  has  been 
full,  a  faint  image  appears,  but  it  is  no  con- 
dition of  success  that  it  should.  The  alka- 
line solution  is  then  poured  back,  and  about 
one-fourth  of  a  three-grain  solution  of  pyro- 
gallic  acid,  without  acetic  or  citric  acid  is 
added,  and  it  is  again  poured  over  the  plate. 
This  causes  the  image  to  appear,  in  all  its 
details,  but  very  faintly.  The  plate  is  then 
well  washed,  and  the  image  is  intensified  to 
its  proper  degree  of  intensity,  with  the  ordin- 
ary pyrogallic  acid  solution,  additioned  with 
a  few  drops  of  nitrate  of  silver.  By  this 
method  of  development,  the  exposure  is  re- 
duced to  twice  or  three  times  that  given  in 
the  wet  collodion  process ;  but  we  repeat  here, 
again,  there  is  a  great  tendency  to  fogging  or 
deposition  of  the  reduced  silver  on  the  shad- 
ows, and  it  requires  great  nicety  of  manipula- 
tion, and,  before  all,  great  patience  in  the 
intensifying,  to  carry  out  the  process  to  a 
successful  result. 


CHAPTER  XXXIX. 

On  Copying. 

As  a  general  thing,  copying  should  be  done 
by  the  light  of  the  sun  reflected  by  means  of  a 


# 


216 

mirror.  The  room  in  which  the  copying  is 
clone,  should,  if  possible,  be  exposed  to  the 
South.  No  light  should  be  admitted  back  of 
the  object  to  be  copied.  It  matters  little  if 
there  be  any  windows  back  of  the  copying 
camera;  but,  in  order  to  avoid  reflections, 
those  on  the  north  side  and  those  back  of  the 
object  should  be  darkened.  This  is,  however, 
also  the  case  in  the  glass  room  used  for  por- 
traits. In  the  morning  the  copying  apparatus 
is  turned  toward  the  East,  and  in  the  afternoon 
toward  the  West. 

When  the  copy  is  to  be  smaller  than  the 
original,  the  ordinary  portrait  camera  can 
be  used,  but  whenever  the  object  is  to  be 
copied  larger,  the  portrait  camera  will  not  be 
found  to  expand  sufficiently.  To  meet  the 
requirements  in  this  case,  a  camera  special- 
ly made  for  the  purpose  is  necessary.  It 
should  expand  as  much  as  four  or  fife  feet, 
and  be  constructed  either  with  bellows  or 
drawers.  It  is  placed  on  a  flat  board,  at  the 
height  of  an  ordinary  table.  At  one  end  of  the 
board  is  placed  vertically  another  board,  one 
and  a  half  or  two  feet  high,  on  which  the  picture 
to  be  copied  is  tacked  or  stuck  fast  with  gum 
paper.  By  a  little  ingenuity,  a  system  can  be 
devised  by  means  of  wdiich  the  picture  is 
raised  or  lowered,  or  moved  toward  the  right 
or  left. 

The  picture  should  be  at  right  angles  with 
the  camera,  so  that  its  shape  may  not  bo 


217 


altered  in  the  copy.  It  should  also  be  placed 
in  such  a  position  that  its  center  is  on  a  level 
with  the  center  of  the  lens. 

The  lens  most  generally  useful  in  copying 
is  the  single  achromatic  lens,  known  common- 
ly as  view  lens.  The  photographer  will  find 
it  advantageous  to  have  two  or  three  of  these, 
of  different  focus;  for  instance,  one  of  six 
inches,  another  one  of  ten  inches,  and  a  third 
one  of  sixteen  inches.  A  quarter  size  and  a 
half  size  portrait  lens,  with  central  stops,  will 
also  answer  the  purpose.  The  lens  to  be 
used  depends  not  on  the  size  the  picture  has 
to  be  made,  but  on  the  size  of  the  original. 
For  instance,  a  six-inch  focus  lens  may  an- 
swer very  well  to  enlarge  a  ninth  size  daguer- 
reotype, etc.,  to  almost  any  size;  but  if  the 
original  was  a  whole  size,  only  the  center 
would  be  sharp  and  well  defined.  In  such 
case,  a  longer  focus  lens>  giving  a  larger  field, 
is  required.  The  aim  is  to  use  only  the  rays 
passing  through  the  central  part  of  the  lens, 
or,  in  other  words,  to  use  only  the  center  of 
the  field. 

When  line-drawings,  engravings,  or  ob- 
jects with  straight  lines  have  to  be  copied, 
the  recommendation  of  using  only  a  small 
part  of  the  field  should  be  more  closely  ad- 
hered to  than  when  the  original  is  a  portrait 
or  landscape.  The  reasons  for  this  is,  that 
when  the  whole  field,  or  the  larger  part  of  it, 
is  made  use  of,  the  single  lens  produces  a  dis- 

19 


218 


tortion  of  the  marginal  lines.  To  illustrate 
this,  suppose  the  photographer  traces,  on  a 
sheet  of  paper,  a  diagram  in  the  shape  of  Fig, 
5,  about  five  inches  square,  and  produces  an 
image  of  it  on  the  ground  glass  of  his  camera 
the  same  size  as  the  original,  by  means  of  a 
lens  which  gives  only  a  circle  of  light,  or  field? 
of  seven  or  eight  inches.  The  image,  instead 
of  being  similar  to  the  original,  will  assume 
the  shape  represented  by  Fig.  6. 


Fig.  7.  Fig.  6.  Fig.  5. 


But  if  a  lens  of  longer  focus  be  used,  for 
instance,  one  giving  a  field  of  fifteen  inches 
diameter,  the  distortion  will  be  scarcely  visible. 

The  portrait,  or  ordinary  double  combina- 
tion lens,  although  quite  free  from  distortion, 
is  not  well  adapted  for  copying  the  style  of 
pictures  referred  to,  on  account  of  the  eurva- 
ture  of  its  field.  The  orthoscopic  lens,  man- 
ufactured by  Voightlander  &  Son,  for  which 
freedom  from  distortion  w^as  at  one  time 
claimed,  produces  a  distortion  of  another  kind, 
illustrated  by  Fig.  7>  The  globe  lens  and  the 
triplet  (either  Ross'  or  Dallmeyer's,)  give 


219 


images  practically  free  from  distortion,  and 
should,  in  consequence,  be  used,  whenever  that 
quality  is  required,  in  preference  to  the  long 
focus  meniscus,  which  requires  a  copying 
camera,  expanding  much  more  than  will  be 
found  practicable. 

Whenever  the  illumination  of  the  image  on 
the  focusing  glass  will  admit  of  it,  it  may  be 
recommended,  to  improve  its  definition,  and 
other  optical  qualities  by  a  use  of  stops.  This 
should,  of  course,  not  be  carried  too  far;  for  a 
point  exists  in  which  the  improvement  in  the 
image,  obtained  by  this  means,  is  not  a  com- 
pensation for  the  disadvantages  resulting  from 
the  long  exposure  of  the  plate. 

The  objects  or  originals  which  the  profes- 
sional photographer  generally  finds  to  copy, 
are  daguerreotypes,  collodion  positives,  either 
on  glass  or  on  iron  plates,  photographs  on 
paper,  ink  and  crayon  drawings,  engravings, 
and  oil  paintings. 

In  copying  daguerreotypes,  a  recommenda- 
tion, which  should  not  be  overlooked,  is  to 
cover  the  shining  brass-work  in  which  the  lens 
is  mounted  with  a  scrap  of  black  velvet,  so  as 
to  avoid  its  reflection  on  the  highly-polished 
plate. 

Daguerreotypes  and  collodion  positives  re- 
quire about  the  same  time  of  exposure.  This, 
howeter,  varies  greatly,  according  to  the  color 
of  the  picture.  Varnished  collodion  positives 
require  a  longer  exposure  than  those  which 


220 


have  not  been  varnished.  Whenever  there 
is  no  harmony  between  the  different  parts  of 
a  picture — for  instance,  when  in  a  portrait  the 
head  is  light  and  the  drapery  very  dark — one 
part  may  be  shaded  off  by  means  of  a  black- 
ened piece  of  card-board,  and  the  exposure 
continued  on  the  other  part  until  the  desired 
effect  is  obtained. 

Photographs  on  paper  require  but  a  short 
exposure.  Whenever  circumstances  will  admit 
of  it,  they  should  be  copied  by  diffused  light, 
in  order  to  avoid  the  disagreeable  roughness 
resulting  from  the  unequality  of  the  paper 
when  copied  by  sunlight.  By  making  the 
photograph  wet,  and  sticking  it  on  a  plate 
glass,  this  roughness  can,  however,  be  avoided. 

Engravings,  drawings,  etc.,  also  require  but 
a  short  time  of  exposure.  It  should  be  such 
that  when  fully  developed  and  fixed,  the  image 
looks  well  as  a  positive.  If  the  exposure  be 
pushed  further,  the  cleanliness  of  the  lines  is 
lost  after  redevelopment.  The  method  of  re- 
development to  be  recommended,  is  that  with 
nitrate  of  silver  and  pyrogallic  acid,  or  sulphate 
of  iron  and  tartaric  acid,  the  film  being  first 
partly  transformed  into  iodide  of  silver  by  the 
application  of  a  solution  of  iodine  and  iodide 
of  potassium.  The  collodion  used  should  be 
simply  iodized,  or  only  contain  a  small  quan- 
tity of  bromide.  When  the  drawing  is  made 
on  a  rough  kind  of  paper,  the  sunlight  should 
be  reflected  on  it  with  as  little  obliquity  as 


221 


possible,  in  order  to  avoid  the  production  of 
shadows  by  the  inequalities  of  its  surface. 

Lead-pencil  drawings  are  among  the  most 
difficult  subjects  to  copy,  on  account  of  the 
reflection  produced  by  the  pencil-marks  and 
of  their  grey  color.  They  require  a  very  short 
exposure,  so  that  the  image  looks  well  as  a 
positive.  As  it  is  often  difficult  to  bring  the 
negative  up  sufficiently  by  redevelopment, 
without  stains  and  irregularities  in  the  sur- 
face, it  is  advisable  to  redevelop  it  only  up  to 
a  certain  point,  and  then  to  intensify  it  with 
bichloride  of  mercury  and  bromide  of  potas- 
sium, or,  instead,  sulphide  of  ammonium. 

Oil  paintings  are  best  copied  by  diffused 
light.  The  glass  house,  or  sky  and  side  light 
room,  used  by  the  portrait  photographer,  is 
well  suited  to  this  kind  of  work.  The  great 
difficulty  consists  in  avoiding  reflections.  To 
attain  this,  the  painting  is  hung  up  one  or  two 
feet  back  of  the  place  ordinarily  occupied  by 
the  sitter,  and  the  light  is  made  to  fall  on  it 
as  much  as  possible  from  the  front.  All  un- 
necessary light,  and  all  that  which  comes  from 
the  sky  or  the  side,  should  be  excluded.  The 
collodion  used  should  be  newly  made,  and  con- 
tain a  maximum  of  bromide,  if  the  non-active 
colors  predominate  in  the  painting,  or  if  it  has 
become  brown  by  age.  Modern  oil  paintings, 
however,  which  are  a  more  faithful  represen- 
tation of  nature,  are  easily  reproduced  with 
the  ordinary  portrait  collodion. 


222 


CHAPTER  XL. 
Out-Door  Photography. 

The  outfit  for  out-door  photography  should 
be  selected  with  reference  to  small  weight, 
compactness  and  portability.  It  should  con- 
sist of  the  following  articles  : 

A  dark  tent  or  developing  box;  a  water- 
bag  ;  a  light  folding  camera  with  plate-holder 
lens,  etc. ;  a  light  and  solid  tripod  stand ;  a 
water  level ;  a  bath  dish  of  gutta  percha  or 
vulcanite ;  a  grooved  box,  with  glass ;  a  soft 
camel  hair-brush ;  a  bottle  of  collodion ;  a 
strong  bottle,  well  wrapped  up,  holding  the 
silver  solution  ;  a  bottle  with  developing  solu- 
tion ;  a  bottle  with  the  pyrogallic  acid  or  tar- 
taric acid  and  iron  redeveloping  solution ;  a 
small  bottle  of  twenty-grain  silver  solution 
for  redeveloping ;  a  bottle  with  fixing  solution ; 
a  bottle  with  glycerine. 

These  articles  should  be  packed  in  two 
light  boxes,  with  strap,  so  as  to  be  easily 
carried — one  of  these  boxes  to  hold  the  cam- 
era, plate-holder,  water-bag,  etc.;  the  other 
to  contain  the  chemicals.  When  a  develop- 
ing box  is  used,  the  chemicals  may  be  packed 
into  it.  The  tripod  stand  can  be  strapped  on 
one  of  the  boxes. 


223 


Fig.  8. 


The  developing  box  is  best  suited  for  small 
plates,  such  as  those  of  the  stereoscopic  and 
I  size.  Figure  8,  represents  one  of  these 
boxes.  Its  dimensions  are,  height,  20  inches ; 
width,  18  inches  ;  depth,  7  inches.  The  door, 
which  is  represented  open,  is  used  to  take  the 
plate-holder  and  plate  in  and  out.    In  it  is  a 


224 


window,  with  a  yellow  glass,  which  can,  11 
necessary,  be  shut.  On  the  slanting  roof  is 
another  yellow  glass.  The  tent  part  of  the 
box  is  made  of  India-rubber  cloth,  and  has 
two  sleeves  to  introduce  the  hands.  It  is  held 
up  by  means  of  brass  rods,  which,  when  the 
box  is  to  be  shut,  bend  inside  of  it.  On  its 
upper  part  are  two  openings  to  apply  the 
eyes,  so  as  to  see  the  inside  while  operating. 
These  can  be  arranged  in  the  same  way  as  in 
a  stereoscope.  The  horizontal  part,  to  which 
the  India-rubber  cloth  is  attached,  is  fitted 
with  a  sink,  made  of  gray  India-rubber  cloth, 
and  to  this  sink  is  fastened  an  India-rubber 
waste-pipe,  which  is  represented  in  the  cut 
hanging  down.  The  whole  box  is  supported 
on  a  light  tripod  stand,  which,  when  not  in 
use,  is  strapped  on  the  side  of  it. 

The  way  to  use  the  box  is  as  follows :  The 
plate  and  plate-holder  are  introduced  in  the 
box,  through  the  door,  and  the  operator  puts 
his  hands  through  the  sleeves  and  prepares 
the  plate,  examining  the  operation  through 
the  holes  in  the  cloth.  The  plate  being* 
ready,  it  is  put  into  the  plate-holder,  taken  out 
of  the  box  through  the  door,  and  exposed. 
The  development  and  fixing  are  done  in  the 
same  way. 

This  developing  box  can  be  modified,  so  that 
the  head  and  upper  part  of  the  body  be  put 
under  the  cloth.  The  tent  part  will  then 
have  to  extend  about  one  and  a  half  feet 


225 


farther,  and  be  made  to  hang  down,  so  as  to 
encircle  the  operator  below  the  waist.  This 
system  gives  more  freedom  of  motion  to  the 
operator,  but  is  very  uncomfortable  on  a  hot  day. 

When  large  plates  have  to  be  used,  it  is 
best  to  have  a  tent,  or  a  van,  covered  with  oil- 
cloth. Many  models  for  tents  have  been  pro- 
posed, all,  more  or  less,  objectionable,  either 
on  account  of  weight  or  solidity.  The  handiest 
one  we  have  used  was  a  piece  of  double-thick 
muslin,  thrown  over  a  tripod  stand  about  eight 
feet  high,  and  extended  by  having  five  or  six 
ropes  attached  by  one  end  to  the  upper  part 
of  the  cloth,  and  by  the  other  to  some  tree  or 
other  object  near  by,  or  to  a  spike  driven  in 
the  ground.  The  objection  to  tents  is,  the 
annoyance  caused  by  the  dust.  They  should 
thus  be  pitched  in  a  grassy  place,  and,  if  nec- 
essary, the  ground  around  should  be  sprinkled 
with  water. 

A  good  water-bag  can  be  made  of  India- 
rubber,  by  taking  a  piece  of  tubing  about  six 
inches  in  diameter,  and  cementing  both  ends  by 
means  of  India-rubber  dissolved  in  benzine, 
inserting  at  one  end  a  mouth  of  hard  rubber, 
through  which  the  water  is  poured  in,  and  on 
the  other  a  tube  about  eight  or  ten  feet  long, 
which  passes  into  the  tent,  or  developing  box, 
through  a  little  hole.  The  bag  is  hung  on  a 
tree,  or  other  object,  and  the  end  of  the  tube 
is  closed  by  means  of  one  of  the  wooden  clips 
used  for  hanging  up  prepared  paper. 


226 


The  camera  should  be  as  light  as  possible, 
and  fold  up  so  as  to  present  but  a  small  vol- 
ume. The  lens  should  be  fixed  on  a  board 
which  slides  up  or  down,  so  as  to  allow  of  more 
sky  or  more  foreground,  according  to  circum- 
stances. The  tripod  stand  should  combine 
the  advantages  of  small  weight  with  that  of 
solidity.  A  light  and  very  solid  stand  can  be 
made  of  the  kind  of  cane  used  for  fishing-rods. 

The  bath  dish  ought  to  be  made  of  a  mate- 
rial which  is  not  liable  to  break.  Vulcanite, 
or  gutta  percha,  answer  best.  If  the  cover  be 
made  to  fit  tightly,  it  will  save  the  carrying  of 
a  bottle  to  hold  the  silver  solution. 

Some  landscape  photographers  cover  the 
plate,  after  it  has  been  developed  and  drained, 
with  a  diluted  solution  of  glycerine,  and  per- 
form the  fixing  and  redeveloping  as  strength- 
ening at  home.  When  this  plan  is  adopted, 
the  outfit  is  considerably  reduced,  no  water, 
fixing  solution  nor  redeveloping  solution  being 
required. 

The  lenses  used  for  making  views,  are  the 
meniscus,  or  single  achromatic  lens,  the  globe 
lens,  the  triplet,  the  orthoscopic,  and,  some- 
times, the  double  combination  or  portrait  lens. 
The  single  achromatic  lens  is  the  best  for  gen- 
eral purposes.  When  sufficiently  diaphragmed, 
it  gives  a  definition  superior  to  that  given  by 
any  other  lens.  For  architectural  subjects, 
it  will  not  answer  so  well,  unless  used  at  a 
sufficient  distance,  on  account  of  the  distor- 


227 

I 

tion  of  the  marginal  lines.  The  globe  lens  is 
free  from  this  defect,  and  is  thus  well  suited 
to  architectural  subjects,  especially  when  there 
is  little  space  in  front. 

The  globe  lens  possesses,  also,  much  depth 
of  focus;  that  is,  it  brings  objects  situated  at 
different  planes  in  focus  at  the  same  time. 
It  is  not  equal  in  definition,  however,  to  the 
single  lens,  and  always  requires  to  be  strongly 
diaphragmed  to  correct  the  spherical  aberra- 
tion. It  has  the  advantage  of  giving  an  image 
including  an  angle  of  view  two  or  three  times 
as  wide  as  that  given  by  the  meniscus. 

The  triplet,  manufactured  by  Dallmeyer, 
(London)  also  gives  images  free  from  distor- 
tion, and  includes  the  same  angle  of  view  as 
the  globe  lens.  It  has  somewhat  less  depth 
of  focus,  but,  when  used  with  a  large  diaphragm, 
is  superior  to  it  in  definition. 

The  same  may  be  said  of  the  triplet  man- 
ufactured by  Ross  as  of  that  made  by  Dall- 
meyer, with  the  exception  that  it  gives  an 
image  including  a  smaller  angle. 

Petzval  orthoscopic  lens,  as  we  have  seen 
already,  gives  an  image  in  which  the  mar- 
ginal lines,  instead  of  bending  inward,  bend 
outward.  Architectural  subjects  may  be  re- 
produced by  it  quite  correctly,  by  tilting  the 
camera  slightly  upward.  The  qualities  of 
the  orthoscopic  lens  are  great  definition  and 
flatness  of  field. 

The  double  combination  or  portrait  lens  is 


used  in  out-door  photography,  when  eveiy 
other  quality  has  to  be  sacrificed  to  rapidity 
of  action,  as,  for  instance,  when  moving  objects 
have  to  be  photographed.  The  great  defect 
of  the  portrait  lens  is  the  curved  field  it  gives. 

The  camera  should  be  perfectly  level.  If  it 
was  pointed  downwafd  or  upward,  the  verti- 
cal lines  in  the  view  would  fall  inward  or 
outward.  If  by  having  the  camera  horizontal 
there  is  too  much  foreground  or  too  much  sky 
in  the  image,  raise  or  lower  the  slide  to 
which  the  lens  is  attached. 

The  most  favorable  moment  to  take  a  view, 
is  when  the  rays  of  the  sun  fall  obliquely  on 
the  object.  When  the  sun  is  right  behind  the 
camera,  the  picture  produced  is  too  flat.  The 
peculiar  manner  of  illumination  depends,  how- 
ever, greatly  on  the  object  itself  and  on  the 
taste  of  the  operator. 

The  camera  should  be  placed  so  that  the 
rays  of  the  sun  do  not  fall  on  the  lens,  in 
order  to  avoid  reflections,  which  would  cause 
fogginess  in  the  picture.  When  the  picture 
includes  a  large  amount  of  strongly  illumin- 
ated sky,  and  a  double  or  triple  lens  is  used,  a 
light  circular  spot  is  seen  in  the  center  of  the 
ground  glass,  which  is  the  more  visible  as  the 
stop  used  is  smaller.  This  appearance  is 
known  to  photographers  by  the  name  of 
ghost.  Single  lenses  are  not  liable  to  it,  it 
being  produced  by  the  reflection  of  the  light 
from  one  lens  to  the  other.    The  only  way  to 


229 


obviate  this  defect,  to  some  extent,  is  to  cut  off 
the  sky  part,  during  the  larger  part  of  the  ex- 
posure, and  allow  it  to  impress  the  sensitive 
plate  for  a  very  short  time  toward  the  end* 
This  is  easily  done  by  using,  as  a  cover  to  the 
lens,  a  small  square  board  hinged  on  the  upper 
part,  so  that  it  can  be  raised  and  lowered. 
By  looking  on  the  ground  glass  it  can  be  set 
in  such  a  position  that  it  cuts  off  the  sky. 
Giving,  then,  three-fourths  of  the  proper  ex- 
posure, it  is  raised  more,  so  as  to  allow  the 
sky  to  be  impressed,  the  rest  of  the  exposure 
is  given,  and  the  lens  is  covered  up.  As  the 
appearance  of  the  ghost  is  generally  accom- 
panied by  a  solarized  sky,  the  short  exposure 
given  to  that  part  of  the  image  prevents  the 
solarization.  When  the  means  described  is  not 
practicable,  on  account  of  the  outline  of  the 
sky  being  irregular,  an  imperfect  remedy  is 
found  in  adapting  in  front  of  the  lens  a  funnel, 
made  of  blackened  pasteboard,  so  that  all  rays, 
not  active  in  producing  the  impression,  be 
excluded. 

The  size  of  a  stop  to  be  used  is  a  matter 
of  consideration  for  the  photographer.  The 
smaller  the  stop,  the  longer  exposure  is  re- 
quired. If  the  length  of  the  exposure  is  no 
object,  a  small  stop  should  be  used,  for  a 
superior  definition  will  be  the  result,  and 
objects,  in  different  planes,  will  be  made 
equally  sharp.  For  a  landscape,  in  which 
there  is  no  principal  object,  to  which  every 


230 


thing  else  should  be  sacrificed,  if  need  be,  the 
focus  should  be  taken  on  a  part  of  the  scenery 
which  is  half  way  between  the  principal  ob- 
jects in  the  foreground  and  those  in  the  back- 
ground. By  inserting  a  stop,  every  plane  is 
then  pictured  with  sufficient  definition,  When 
a  picture  is  wished  of  a  single  object,  such  as 
a  building,  or  a  monument,  the  focus  is  taken 
on  a  point  half  way  between  the  center  and 
the  edge  of  the  object.  In  taking  the  focus, 
make  use  of  a  magnifying  glass.  Darlot's  eye- 
piece is  very  well  suited  to  the  purpose;  it 
magnifies  the  image  sufficiently  to  see  plainly 
the  smallest  details.  It  is  composed  of  a  com- 
bination of  lenses,  set  in  a  tube.  This  tube 
itself  slides  into  another  tube,  and  can  be 
fastened  at  any  point,  by  means  of  a  screw. 
The  eye-piece,  before  being  used,  is  to  be  set 
to  the  eyesight  of  the  operator.  This  is  done 
in  the  following  way :  Take  a  piece  of  ground 
glass,  make  a  pencil-mark  on  the  ground  side, 
and  set  it  against  the  window,  the  ground  side 
outward.  Then  put  the  mouth  of  the  eye- 
piece against  it,  and  draw  the  inside  tube 
forward  or  backward,  just  as  in  focusing, 
until  you  see  a  sharp  image  of  the  pencil-mark, 
after  which  you  tighten  the  screw.  All  the 
operator  has  to  do  now,  when  he  wishes  to 
look  at  the  focus,  is  to  apply  it  against  the 
ground  glass  of  the  camera. 

In  photographing  foliage,  a  bromo-iodized 
collodion  is  necessary.     Sufficient  detail  is 


231 


brought  out  by  a  long  exposure.  The  image 
is  generally  weak,  and  needs  a  good  deal  of 
redeveloping  or  strengthening  to  acquire  suffi- 
cient intensity.  In  such  subjects,  the  sky  is 
generally  thin  from  being  solarized,  unless  the 
contrivance  spoken  of  above,  to  give  a  shorter 
exposure  to  the  sky  than  to  the  landscape^ 
be  made  use  of. 


CHAPTER  XLL 

Instantaneous  Photography. 

The  term  instantaneous,  which  has  been 
adopted  by  photographers,  is,  in  the  proper 
sense,  wrong;  for  the  so-called  instantaneous 
pictures  are  taken  in  a  space  of  time  which 
is  appreciable,  as  can  be  seen  in  many  of 
them,  where  the  outlines  of  moving  objects 
are  found  to  be  less  sharp  and  defined,  than 
those  of  other  immovable  objects  around. 

The  conditions  required  to  produce  pictures 
with  the  shortest  exposure  are,  a  good  light, 
the  use  of  a  quick-working  lens,  and  the  use 
of  solutions  in  the  most  sensitive  condition. 

Pictures  of  moving  objects  should  only  be 
attempted  to  be  taken  by  a  very  good  light. 
The  light,  as  we  all  know,  is  most  actinic  in 
the  spring,  between  the  hours  of  ten  and  two, 
and  on  a  sunshiny  day,  or  while  the  sky  is 
covered  with  white  clouds.    In  these  condi- 


232 


tions,  supposing  the  lens  and  chemicals  to 
answer  all  requirements,  small  portraits  of 
fair  complected  persons  maybe  taken  in  a  glass 
room,  in  from  one  to  three  seconds,  and  out- 
side views  as  rapidly  as  the  lens  can  be  un- 
covered and  covered  up  again.  A  good  deal 
will  depend,  however,  on  the  subject,  for  dis- 
tant landscapes  and  sea  scenes  are  taken  much 
quicker  than  street  scenes,  etc. 

The  lens  is  the  next  thing  to  be  considered. 
It  should  be  of  short  focus,  and  used  with  a 
wide  aperture.  This  precludes  the  use  of  the 
single  lens  and  of  the  globe  lens,  and  of  all 
such  lenses  which  can  not  be  used  without 
small  stops.  The  double  combination,  or  por- 
trait lens,  is  the  one  best  adapted  to  this  kind 
of  work.  It  should  be  of  a  short  focus,  and 
possess  every  possible  excellency,  as  no  small 
diaphragms  can  be  used  to  correct  its  faults. 
The  English  opticians  manufacture  lenses  ex- 
pressly for  the  purpose.  Among  these,  the 
only  one  which  came  to  our  notice,  is  Dall- 
meyer's  stereoscopic  lens,  which,  we  think> 
answers  all  requirements,  and  is  as  near  to 
perfection  as  it  can  be  made.  This,  we  say, 
without  wishing  to  detract  from  the  merits  of 
the  lenses  of  other  makers,  having  had  no 
occasion  to  try  them. 

The  most  favorable  condition  of  the  solu- 
tions, as  far  as  sensitiveness  is  concerned,  is 
the  third  thing  to  be  considered.  The  collo- 
dion should  be  made  with  pyroxyline,  prepared 


233 


at  a  low  temperature,  (about  120  degrees,) 
and  with  acids  in  about  equal  parts.  The 
character  of  such  pyroxyline,  is  to  give  a  rapid 
collodion,  producing  little  intensity.  Inten- 
sity should  always  be  avoided,  for  intense 
collodion  never  works  quick.  The  aim  is  to 
obtain  an  image  sufficiently  developed,  how- 
ever thin  it  may  be,  and  to  bring  it  up  after- 
wards by  redeveloping  or  strengthening.  The 
collodion  should  also  be  iodized  to  the  creamy 
state,  and  contain  a  full  proportion  of  bromide. 
Four  grains  to  the  ounce  of  iodide  of  ammonium, 
and  three  of  bromide  of  cadmium,  is  a  very 
good  proportion.  This  collodion  will  keep  sev- 
eral weeks  in  its  most  sensitive  state.  Col- 
lodion containing  nothing  but  the  cadmium 
salts,  only  acquires  its  maximum  of  sensitive- 
ness after  having  been  kept  for  several  weeks. 

The  bath  should  be  made  with  pure  fused 
and  recrystalized  nitrate  of  silver,  and  should 
only  contain  a  trace  of  nitric  acid.  After  it 
has  been  worked  some  days,  it  will  be  re- 
marked that  the  plates  are  not  as  sensitive  as 
before.  In  this  case  there  is  no  remedy  but 
to  make  a  new  one.  The  ordinary  iron  de- 
veloper is  the  one  best  suited.  It  may  be 
used  in  the  proportion  of  one  ounce  of  sul- 
phate of  iron  to  sixteen  or  twenty  of  water. 

Some  precautions  should  be  observed,  which 
are  indispensable  to  success.  A  rapidly  moving 
object,  at  a  short  distance,  should  be  taken 
moving  toward  the  operator  or  away  from 

20 


234 


Mm,  and  never  while  it  passes  him,  for  the 
shortest  exposure  could  not  prevent  it  from 
being  blurred  in  the  picture.  Great  care 
should  always  be  taken  to  admit  no  diffused 
light  in  the  camera.  To  this  effect,  fix  in 
front  of  the  tube  a  funnel  made  of  card-boardr 
blackened  inside  and  projecting  about  six 
inches,  and  have  your  stops  between  the  ^ 
lenses.  Ascertain,  also,  if  no  light  enters 
through  the  sliding  tubes,  and  cover  the 
camera  with  a  black  cloth  while  you  are 
exposing.. 

The  caps  with  which  lenses  are  provided, 
can  not  be  taken  off  and  put  on  again  quick 
enough.  A  soft  hat  or  cap,  or  a  black  cloth, 
will  answer  the  purpose  better.  When  the 
exposure  has  to  be  shorter  than  can  be  given 
by  this  means,  the  drop  shutter  can  be  used. 
It  is  composed  of  a  thin  board,  pierced  with  a 
hole,  the  same  diameter  as  the  lens,  which 
slides  in  a  groove  in  front  of  the  lens.  The 
lens  being  covered  by  the  lower  part  of  the 
slide,  the  latter  is  allowed  to  drop,  and  the 
lens  is,  for  a  moment,  uncovered.  The  same 
arrangement  can  be  used  in  a  horizontal  posi- 
tion. In  this  case,  the  shutter  is  provided 
with  an  India-rubber  spring  which  is  stretched 
and  then  let  loose  again  by  touching  a  catch. 

It  is  important,  in  order  to  secure  the 
greatest  degree  of  sensitiveness,  that  as  short 
a  time  should  elapse  between  the  preparation 
of  the  plate  and  the  development  as  is  possi- 


235 


ble.  The  operator  should  thus  have  his  tent, 
or  developing-box,  near  at  band, 


CHAPTER  XLIL 

Photography  on  Painters'  Canvas. 

Ever  since  enlarged  prints  on  paper  were 
made,  it  has  been  the  aim  of  photographers, 
who  practice  this  branch  of  the  art,  to  pro- 
duce similar  pictures  on  the  canvas  •  used  by 
painters.  The  first  attempts  consisted  in  salt- 
ing and  silvering  the  canvas  in  the  same  way 
as  the  paper;  but  the  coating  of  white-lead 
with  which  the  canvas  is  covered,  not  being 
a  porous  substance,  the  prints  obtained  were 
very  faint.  A  modification  of  the  glass  albu- 
men process  was  then  tried.  The  canvas  was 
washed  with  an  alkali,  coated  with  iodized 
albumen,  silvered,  developed  with  gallic  acid, 
and  fixed  with  hyposulphite.  This  gave  from 
the  start  beautiful  results,  but  the  process  was 
soon  given  up,  on  account  of  the  peeling  and 
cracking  of  the  film  of  albumen  after  the  pho- 
tograph had  been  painted.  The  writer  of  this, 
who  was  then,  and  is  now,  engaged  in  the 
enlarging  business,  substituted  a  thin  solution 
of  gelatine  to  the  albumen,  and  met  with  such 
success  that  he  has  continued  to  use  the  pro- 
cess ever  since.  It  may  be  thought  that  the 
gelatine,  like  the  albumen,  leaving  a  film  on 


236 


the  surface  of  the  canvas,  the  image  is  also 
liable  to  peel  off  and  crack,  but  this  is  not  the 
case.  For,  while  the  film  of  albumen  is  horny 
and  like  parchment,  and  consequently  adheres 
but  imperfectly,  the  gelatine  film  is  very  por- 
ous and  adherent,  and  leaves  the  canvas  in  the 
same  state  as  it  was  before.  It  is  this  process 
which  we  now  propose  to  describe;  we  will 
divide  it  as  follows  : 

1.  Repainting  the  canvas. 

2.  Cleaning. 

3.  Iodizing. 

4.  Sensitizing. 

5.  Exposure. 

6.  Developing. 

7.  Fixing  and  washing. 

Repainting  the  Canvas. 

Different  kinds  of  canvas  give  different 
results.  Some  kinds  are  easily  cleaned  by 
rubbing  with  a  piece  of  canton-flannel,  moist- 
ened with  alcohol ;  others  require  rubbing  with 
a  sponge  and  soap-water,  to  which  an  alkali 
has  been  added.  One  variety  requires  a  longer 
exposure  than  another,  and  almost  every 
sample  gives  a  picture  different  in  appearance. 
To  work  with  uniformity,  and  produce  the 
best  results,  it  is  thus  advisable  to  give  tcx  the 
canvas  a  coat  of  paint  always  prepared  in  a 
uniform  way.  The  paint  we  have  found  to 
answer  the  best,  is  made  with  one  pound  of 
white-lead,  ground  with  oil,  and  eight  fluid 


237 


ounces  of  turpentine,  or  common  petroleum 
benzine.  (The  refined  petroleum  benzine  and 
that  made  from  coal  or  coal-tar  is  too  volatile.) 
The  white  lead  is  the  best  kind  used  for  com- 
mon purposes,  and  is  sold  in  kegs.  The 
white  lead  and  turpentine  are  well  mixed,  and 
the  mixture  is  strained  through  a  coarse  cloth, 
and  applied  with  a  flat  varnish  brush.  After 
two  or  three  days,  the  paint  is  perfectly  dry, 
and  the  canvas  is  ready  for  the  next  operation. 

CleXning  of  the  Canvas. 

The  canvas  is  now  rubbed  with  a  piece  of 
canton-flannel  moistened  with  alcohol.  The 
object  of  this  is  to  take  off  the  greasiness,  so 
that  the  iodizing  solution  adheres  to  the  sur- 
face. The  rubbing  should  be  done  gently,  so 
that  the  paint  does  not  come  off.  It  is  suffi- 
cient to  go  over  the  surface  two.  or  three 
times,  after  which,  the  canvas  is  rubbed  dry 
with  a  new  piece  of  flannel. 

Iodizing  the  Canvas. 

The  iodizing  solution  is  prepared  according 
to  one  of  the  two  following  formulas. 


Gelatine   200  grains. 

Iodide  of  Potassium   400  " 

Bromide  of  Potassium   100  " 

Chloride  of  Ammonium  .   100  u 

Water   80  ounces. 

Gelatine   200  grains. 

Iodide  of  Potassium   400  " 

Bromide  of  Potassium   200  " 

Water   80  ounces. 


238 


The  first  solution  is  used  when  the  negative 
is  thin,  and  the  second  when  it  is  intense. 

The  gelatine  is  soaked  in  the  water  until  it 
is  well  softened.  It  is  then  dissolved  by  a 
gentle  application  of  heat,  the  other  ingredi- 
ents are  added,  and  it  is  filtered  through  a 
tuft  of  cotton-wool  previously  moistened  with 
alcohol. 

The  iodizing  solution  is  applied  by  means 
of  a  flat  brush,  and  the  canvas  set  to  dry  in 
a  warm  room,  free  from  dust.  If  the  coating 
should  dry  in  lines,  the  fault  lays  in  the  clean- 
ing. It  should  then  be  washed  off  with  warm 
water,  and  cleaned  again. 


The  silver  solution  is  prepared  according 
to  the  following  formula : 


Old  collodion  silver  solutions  reduced  to 
the  proper  strength,  and  additioned  with 
acetic  acid,  can  be  used  up  very -economically 
in  this  process. 

The  silver  solution  can  not  be  applied  with 
cotton,  for  the  thin  film  of  gelatine  would  rub 
off.  The  way  to  proceed  is  as  follows  :  Get  a 
square  frame  made  of  walnut,  one  inch  thick, 
two  and  a  half  inches  high,  and  the  size  of 
the  canvas.  Grive  it  several  coats  of  shellac 
dissolved  in  turpentine.    Then  take  India- 


Sensitizing  the  Canvas. 


Nitrate  of  Silver  . 
Distilled  Water.... 
Acetic  Acid  No.  8. 


1  ounce. 
16  ounces. 

2  ounces. 


239 


rubber  tubing,  one-half  inch  thick,  pass  it 
through  a  hot  mixture  of  wax  and  turpentine, 
let  dry,  and  tack  it  around  the  frame  with 
thin  nails  about  one-half  inch  long,  driving 
the  nails  through  the  outer  surface  of  the  tube, 
so  that  the  silver  solution  can  not  come  in 
contact  with  the  iron.  The  canvas  is  now 
laid  on  the  tubing  and  is  fastened  to  the  frame 
by  means  of  wooden  clamps.  The  whole  thus 
forms  a  tray  of  which  the  canvas  is  the  bottom, 
and  which  is  kept  from  leaking  by  the  tubing, 
To  sensitize  the  canVas,  tilt  it  up  to  an 
angle  of  forty-five  degrees,  pour  the  solution 
in  the  lower  part  of  the  tray,  and,  by  bringing 
this  back  to  a  horizontal  position,  cause  the 
fluid  to  flow  over  the  surface.  Keep  in 
motion  by  moving  one  end  of  the  tray  up  and 
down  for  three  or  four  minutes,  and  then  pour 
into  a  bottle.  The  canvas  is  now  ready  for 
exposure. 

The  silver  solution  should  be  used  but 
once,  for  it  becomes  contaminated  by  the 
gelatine,  and  would  give  foggy  pictures.  It  is 
best  to  precipitate  it  with  copper  or  salt,  with- 
out waiting  till  it  becomes  discolored. 

Exposure. 

The  focus  should  have  been  taken  pre- 
viously to  the  sensitizing.  The  canvas  is  then 
put  in  the  same  place  on  the  stand  or  easel 
which  it  occupied  before,  and  the  sun  is 
turned  on. 


240 


The  time  of  exposure  varies  considerably. 
It  depends  on  the  strength  of  the  light,  the 
intensity  of  the  negative,  the  proportion  of 
the  enlargement,  and  the  formula  used  for 
iodizing.  The  formula,  without  chloride  of 
ammonium,  produces  the  most  sensitive  sur- 
face, and  is,  consequently,  better  suited  for 
intense  negatives.  The  exposure  should  gen- 
erally be  continued  until  the  image  is  partly 
visible.  When  the  negative  is  intense,  it  will 
have  to  be  quite  plainly  marked,  but  when  it 
is  very  weak,  it  may  be  necessary  to  proceed 
with  the  development  before  the  least  trace 
of  an  image  can  be  seen.  When  negatives 
are  made  on  purpose  for  this  kind  of  work, 
they  should  be  made  clear  and  transparent  in 
the  shadows,  and  without  density  in  the  high 
lights.  Such  negatives  will,  with  the  first 
formula  for  iodizing,  give  the  best  prints. 

How  long  the  exposure  will  have  to  be,  is, 
as  can  be  concluded,  from  what  we  have 
already  said,  entirely  a  matter  of  judgment, 
guided  by  experience.  We  have  made  can- 
vas pictures  in  five  seconds,  and  at  other 
times  have  been  obliged  to  expose  eight  and 
ten  minutes. 

Develop31ent  of  the  Image. 

The  image  is  developed  with  a  solution  of 
gallic  acid,  slightly  acidulated  with  acetic 
acid.  The.  strength  of  this  solution  varies 
according  to  the  temperature.    In  warm 


241 


weather,  the  saturated  solution,  diluted  with 
twice  its  bulk  of  water  will  answer.  In  cold 
weather,  it  may  be  used  twice  as  strong. 
Very  little  difficulty  will  be  found  in  this  part 
of  the  manipulation,  for  if  a  weak  solution  is 
used,  the  only  trouble  is  that  the  image  will 
come  out  slowly. 

The  gallic  acid  solution  is  flowed  over  the 
surface  of  the  canvas  in  the  same  way  as  the 
silver  solution. 

If  the  development  proceeds  too  slowly, 
from  under  exposure,  or  any  other  cause,  it 
can  be  activated  by  adding  a  little  silver  solu- 
tion and  a  few  drops  of  a  solution  of  acetate 
of  ammonia,  or  acetate  of  soda. 

When  the  image  is  fully  brought  out,  further 
development  should  be  stopped,  by  adding  a 
few  drachms  of  a  solution  of  common  salt. 
The  canvas  is  then  rinsed,  and  is  ready  for 
the  next  operation. 

Fixing  and  Washing. 

The  fixing  is  done  with  the  ordinary  solu- 
tion of  eight  ounces  of  hyposulphite  of  soda 
in  one  quart  of  water.  It  is  advisable  to  per- 
form this  operation  after  the  canvas  is  taken 
off  the  frame,  for  if  any  hyposulphite  remained 
on  the  wood,  or  got  in  the  tubing,  the  next 
attempt  would  result  in  a  failure,  the  canvas 
becoming  entirely  black  on  applying  the  de- 
veloper. The  hyposulphite  solution  is  poured 
over  the  surface,  and  flowed  forward  and  back- 

21 


242 


ward,  after  which,  the  picture  is  washed  under 
a  tap  for  five  or  ten  minutes. 

Observations. 

*  After  a  picture  has  been  made,  the  frame 
is  washed,  by  means  of  a  sponge,  with  soap- 
water,  to  which  a  little  cyanide  of  potassium 
has  been  added.  It  is  then  rinsed  in  an 
abundance  of  water  and  set  to  dry, 

A  canvas  which  has  been  used,  is  also 
cleaned  with  soap-water  and  cyanide.  It  will 
generally  have  to  be  painted  over  again,  for 
the  cyanide  solution  will  take  off  part  of  the 
paint. 

The  quantity  of  silver  solution  to  be  used 
for  a  twenty-nine  by  thirty-six  picture,  can, 
by  skillful  manipulation,  be  reduced  to  eight 
or  ten  ounces.  The  silver  can  be  precipitated 
out  of  this  solution  by  copper  or  salt,  and 
afterward  transformed  again  into  nitrate. 


CHAPTER  XLIIL 

Binocular  Vision  —  The  Stereoscope — How  to  take 
Stereoscopic  Pictures. 

When  a  solid  object  is  examined  with  both 
eyes,  each  eye  receives  different  impressions, 
the  right  eye  seeing  more  of  the  right  side  of 
the  object,  and  the  left  more  of  the  left  side. 
These  two  impressions  combining  together. 


243 


form  an  image,  which  conveys  to  the  mind  of 
•  he  observer  the  relative  proportions  of  the 
hject  examined  better  than  if  the  object  was 
viewed  by  either  eye  separately.  In  other 
terms,  the  object  is  seen  more  solid. 

If  from  the  object,  which  we  will  suppose 
to  be  a  marble  bust,  two  photographs  are 
taken  from  two  points,  two  and  a  half  or  three 
inches  distant  from  each  other,  and  the  left 
hand  photograph  is  examined  by  the  left  eye, 
while  the  right  hand  one  is  examined  by  the 
right  eye,  the  two  images  will  resolve  them- 
selves in  one,  and  the  bust  will  have  the 
appearance  of  being  solid,  or  standing  out  in 
relief. 

To  facilitate  the  examining  of  such  pictures, 
an  instrument  is  used  which  is  called  a  stereo- 
scope.  A  stereoscope  is  a  box  made  of  wood 
or  board,  fitted  at  one  end  with  two  lenses,  or 
prisms,  at  a  distance,  from  center  to  center,  of 
two  and  a  half  or  two  and  three-fourth  inches. 
The  two  pictures,  mounted  side  by  side  on  a 
piece  of  card-board,  are  called  a  stereograph. 
The  stereograph  is  placed  at  one  end  of  the 
box,  at  about  six  inches  from  the  lenses.  The 
stereoscope  has,  in  the  middle,  between  the 
lenses,  a  piece  of  board  or  wood,  which  divides 
it  in  two  compartments,  so  that  each  eye  can 
only  see  one  image. 

It  is  easy  to  understand  that  only  solid 
objects  can  be  used  as  subjects  for  the  stereo- 
scope.   For  if  a  drawing  or  engraving  be  con- 


244 


sidered  with  each  eye  separately,  the  image 
conveyed  to  one  is  exactly  the  same  as  that 
conveyed  to  the  other.  Solid  objects  at  a 
great  distance,  also,  do  not  appear  in  relief, 
and  photographs  of  them,  taken  from  two 
points  corresponding  to  the  eyes,  will  have 
no  stereoscopic  effect  when  examined  in  the 
•stereoscope. 

Stereoscopic  pictures  are  generally  taken 
by  means  of  a  camera  fitted  with  two  lenses, 
of  equal  focal  length  and  rapidity  of  action. 
Such  a  camera  is  called  binocular.  The  lenses 
best  adapted  to  the  purpose  are  those  of 
shorter  focus,  as  they  allow  a  wide  angle  of 
view  to  be  included.  For  groups  or  indoor 
work,  the  double  combination  or  portrait 
lenses  are,  of  course,  the  most  useful.  They 
should  be  of  the  quarter  or  third  size,  and 
not  over  four  and  a  half  inches  in  focal  length. 
For  moving  out-door  scenes,  they  are  also  to 
be  preferred,  as  they  allow  of  being  used  with 
a  larger  diaphragm,  thus  giving  a  very  lumin- 
ous image.  For  landscapes,  two  single  menis- 
cus, of  short  focus,  are  recommended,  or,  in 
case  pictures  are  wanted  including  a  very 
wide  angle  of  view,  the  two  and  a  half  or 
three-inch  focus  globe  lens. 

When  the  object  is  at  a  short  distance  from 
the  camera,  or  when  the  picture  includes 
many  objects  in  the  foreground,  the  stereo- 
scopic effect  is  all  what  can  be  desired.  But 
when  the  principal  object  is  at  a  considerable 


245 


distance,  and  the  foreground  presents  an  even 
surface,  such,  as  a  sheet  of  water  or  a  lawn,  no 
relief  is  perceptible,  and  it  becomes  necessary 
to  make  the  two  pictures  from  two  points 
wider  apart  than  the  distance  between  the 
eyes.  It  is  true,  the  effect  will  then  be  un- 
natural, for  beyond  a  certain  distance  the  eyes 
perceive  no  relief.  What  is  wanted,  however, 
is  to  make  distant  objects  appear  as  if  they 
were  taken  from  points  nearer  to  them,  for 
otherwise  they  would  be  but  uninteresting 
subjects  in  the  stereoscope.  No  positive  rules 
can  be  given  as  to  the  separation  between  the 
two  positions.  One  foot  for  every  fifty  feet 
distance  from  the  main  object,  will,  however, 
generally  be  found  to  answer. 

To  make  stereoscopic  negatives  from  two 
points  distant  more  than  two  and  a  half  or 
three  inches,  use  a  small  camera  with  a  double 
plate-holder,  so  arranged  that  only  half  of  the 
plate  be  exposed  at  a  time,  the  other  half 
remaining  covered  by  the  slide.  This  camera 
is  made  to  slide  right  and  left  on  a  frame 
of  oblong  shape,  two  or  three  feet  long.  The 
frame  itself  is  fixed  to  the  tripod  stand  by 
means  of  a  screw,  driven  in  the  center  of  the 
front  part.  The  way  to  operate  it  is  as  fol- 
follows:  Slide  the  camera  in  the  center  and 
focus,  then  move  it  toward  the  left,  turn  the 
frame  so  that  the  objects  occupy  the  same 
position  on  the  ground  glass  which  they  did 
when  the  camera  was  in  the  center,  and  make 


246 


the  left  hand  picture  on  the  right  half  of  the 
plate.  Now  slide  the  camera  toward  the 
right,  turn  the  frame  in  the  opposite  direction 
so  that  the  objects  to  be  represented  fall  again 
in  the  same  place,  and  make  the  right  hand 
picture  on  the  left  half  of  the  plate.  The 
right  and  left  positions  of  the  camera  can  be 
indicated  by  putting  a  peg  on  each  side,  in 
holes  provided  for  the  purpose.  To  regulate 
the  motion  of  the  frame,  mark  in  the  middle 
of  the  back  part,  an  arc  of  a  circle,  of  which 
the  center  is  the  screw  by  which  the  frame  is 
fastened  to  the  tripod  stand.  This  arc  of  a 
circle  should  be  divided  in  sixteenths  of  an 
inch.  A  small  hand  is  fixed  to  the  stand. 
When  focusing,  the  hand  and  center  division 
should  correspond.  In  making  the  right  hand 
picture,  the  frame  should  be  moved  as  many 
divisions  to  the  right  as  it  was  to  the  left. 

In  mounting  stereographs  printed  from  neg- 
atives made  with  the  binocular  camera,  the 
position  of  the  prints  should  be  inverted ;  that 
is,  the  left  hand  print  should  be  brought  to 
the  right,  and  the  right  hand  one  to  the  left. 
"When  the  negative  is  made  with  the  one-lens 
camera,  as  described  above,  the  respective 
positions  of  the  prints  are  maintained.  Care 
should  be  taken  that  the  two  pictures  be  not 
more  distant  from  center  to  center  than  two 
and  a  half  or  two  and  three-fourths  inches, 
this  being  the  ordinary  distance  between  the 
eyes.     Two  and  three-fourths  is  generally 


247 


preferred,  as  it  allows  more  subject  to  be 
included,  and  requires  but  little  strain  on  the 
eyes  in  case  these  should  be  nearer  together. 


CHAPTER  XLIV. 

Transparent  Positives — The  Opaltype — Enlarging 
Negatives. 

If  a  negative  be  put  against  a  pane  of  glass 
in  a  window,  and  be  copied  with  the  camera, 
by  means  of  the  wet  collodion  process,  the 
copy  produced  will  be  a  transparent  positive. 
This  means  of  producing  positives  is  very 
simple,  but  is  quite  imperfect,  for  the  followr- 
ing  reasons:  1st.  The  diffused  light  which 
enters  the  camera  from  all  sides,  causes  the 
image  to  be  fogged.  2d.  The  action  of  the 
light  is  not  equal  on  all  parts  of  the  plate,  the 
lower  part  being  less  acted  upon  than  the 
higher  part.  The  remedies  to  these  defects 
are  easily  suggested.  1st.  All  light  should  be 
excluded  except  that  which  comes  through 
the  negative.  2d.  Instead  of  the  light  of  the 
horizon,  the  light  of  the  zenith  should  be  used; 
that  is,  the  camera  should  be  raised  at  an 
angle  of  about  forty-five  degrees  toward  the 
north,  and  the  negative  put  in  a  position 
parallel  to  it. 

An  apparatus  well  adapted  to  the  produc- 


• 


248 


tion  of  transparent  positives  is  a  long  box,  at 
one  end  of  which  is  a  groove  for  the  negative, 
and  at  the  other  end,  one  for  the  ground 
glass  or  plate-holder.  The  lens  should  be  half- 
way between  the  two,  when  the  print  has  to 
be  of  the  same  size  ;  nearer  the  negative  when 
to  be  larger,  and  nearer  the  ground  glass 
when  to  be  smaller.  The  best  arrangement 
is,  to  have  the  groove  for  the  board  holding 
the  lens,  and  that  for  the  ground  glass,  move- 
able forward  and  backward.  The  distance 
between  the  negative  and  lens,  and  lens  and 
ground  glass,  and  consequently  the  length  of 
the  box,  depends  on  the  equivalent  focus  of 
the  lens.  The  longer  the  focus  of  the  lens,  the 
longer  the  box  has  to  be.  . 

Instead  of  the  apparatus  just  described,  an 
ordinary  solar  camera  can  be  used  to  good  ad- 
vantage. The  condensing  lens  is  removed, 
and  when  the  sun  shines,  a  ground  glass  is 
put  in  its  place.  The  negative  is  put  in  the 
rack,  and  the  image  produced  by  the  lens  is 
projected  on  the  ground  glass  of  a  camera 
placed  on  a  solid  stand.  The  reflector,  or 
heliostat,  is  worked  in  the  ordinary  way. 
When  the  sky  is  covered,  it  should  be  kept 
as  much  as  possible  in  the  position  it  would 
occupy  if  the  sun  was  visible. 

The  lenses  most  suitable  are  those  which 
give  a  flat  field  and  great  definition.  The 
orthoscopic,  and  either  Ross'  or  Dallmeyer's 
triplets,  are  the  best  for  this  purpose.  Single 


249 


lenses  and  portrait  lenses  can  also  be  used  in 
some  cases. 

Negatives  made  on  purpose  to  produce  trans- 
parent positives,  should  be  thin  and  trans- 
parent, and  possess  great  detail.  The  collo- 
dion used  should  be  new,  and  with  a  full  pro- 
portion of  bromide,  so  that  it  works  with  little 
contrast.  When  a  transparent  positive  is  to 
be  made  of  an  intense  negative,  the  aim  should 
be  to  procure  collodion  producing  so  little 
intensity,  that  for  ordinary  purposes  it  would 
be  worthless.  The  silver  bath  and  developer 
are  the  same  as  for  ordinary  work.  The  time 
of  exposure  should  be  regulated,  so  that  the 
half  tones  be  well  reproduced.  The  fixing  is 
done  with  cyanide  of  potassium.  After  fixing 
and  washing,  the  picture  requires  to  be  toned. 
This  is  done  by  blackening  the  film  with  a 
solution  of  bichloride  of  mercury,  washing,  and 
then  applying  a  one-grain  solution  of  chloride 
of  gold. 

The  opaltype  is  made  in  the  same  way  as 
the  transparent  positive,  using  opal  instead 
of  transparent  glass.  The  opaltype  is  ex- 
amined either  by  reflected  or  transmitted  light. 
It  is  a  very  beautiful  style  of  picture,  which 
promises  to  become  very  popular  on  account 
of  its  pure  whites,  and  the  facility  with  which 
it  takes  dry  colors. 

The  apparatus  described  above  can  be  made 
very  useful  for  copying  and  enlarging  nega- 
tives.   This  is  done  by  copying  a  transparent 


250 


positive  from  the  original  negative,  and  then 
copying  this  positive  again  to  a  negative  in 
the  same  way.  The  success  of  the  operation 
depends  mostly  on  the  qualities  of  the  trans- 
parent positive.  It  should  not  be  larger  than 
a  half  plate,  be  made  with  an  excellent  instru- 
ment, and  the  exposure  timed  so  that  no 
detail  be  lost.  It  is  not  necessary  to  tone  it 
with  bichloride  of  mercury  and  gold. 

Negatives  enlarged  by  this  process  possess 
many  advantages  over  those  made  directly 
with  a  large  lens.  Where  the  use  of  mam- 
moth cameras  requires  one  or  two  minutes  of 
exposure,  thus  trying  greatly  the  patience  of 
the  sitter,  a  negative  for  enlarging  is  pro- 
duced in  ten  or  twenty  seconds.  On  the  other 
hand,  large  lenses  are  alwrays  less  perfect  than 
small  ones.  A  half  or  quarter  size  portrait 
lens  will,  at  a  certain  distance  from  the  sitter, 
produce  an  image  practically  correct  in  pro- 
portion, when  a  mammoth  size  will,  at  the 
same  distance,  reproduce  the  original  out  of 
shape.  Examine,  on  the  other  hand,  a  head, 
three-fourths  or  one  inch  in  size,  made  with  a 
good  half  size  lens,  and  you  will  find  every 
part  sharp  and  well  defined.  A  head  made 
with  a  mammoth  camera  possesses  no  such 
qualities.  If  the  focus  is  taken  on  one  plane, 
the  other  planes  will  appear  blurred ;  so  we 
see,  in  most  large  pictures,  the  eye  well 
defined,  and  the  hair,  beard,  and  shoulders 
out  of  focus.    This  defect  is,  of  course,  reme- 


251 


died,  to  some  extent,  by  the  use  of  stops;  but 
this,  again,  increases  the  time  of  exposure. 

The  original  negative  made  for  enlarging, 
should  not  be  larger  than  quarter  or  half 
size.  It  should  be  made  with  greater  care 
than  is  generally  taken  for  ordinary  negatives. 
The  collodion  should  be  thin,  and  made  with 
the  best  pyroxyline,  so  that  the  film  be  struc- 
tureless. Clean  manipulation  is  indispensa- 
ble; in  short,  the  operator  should  keep  in 
mind,  that  the  least  imperfection  will  become 
more  apparent  in  magnifying. 

The  process  described  has  this  great  ad- 
vantage for  enlarging  over  the  solar  camera 
process,  that  it  can  be  practised  in  all  kinds 
of  weather.  The  photographer  is  thus  enabled 
to  make  his  enlarged  negatives  on  dull  days, 
when  he  is  not  otherwise  occupied,  while  the 
solar  camera  can  only  be  used  on  clear  days, 
when  he  is  generally  kept  busy  in  the  portrait 
room. 


CHAPTER  XLV. 

Recovery  of  Silver  from  Old  Solutions — Taper 
Clippings,  Washings,  etc. 

As  only  a  small  quantity  of  the  silver  used 
?n  photographic  processes,  goes  to  constitute 
the  image,  it  is  greatly  to  the  interest  of  the 
photographer  to  keep  the  washings,  and  other 


252 


wastes,  in  order  to  recover  the  silver  they 
contain. 

Old  solutions  out  of  order,  either  those  used 
for  sensitizing  collodion  plates,  or  for  prepar- 
ing paper,  are  precipitated  by  leaving  them 
in  contact  with  a  copper  plate.  The  metallic 
silver  thus  obtained,* is  well  washed,  redis- 
solved  in  nitric  acid,  evaporated  and  fused, 
until  the  small  quantity  of  nitrate  of  copper, 
which  is  always  present,  is  decomposed.  The 
nitrate  thus  obtained  can  then  be  used  as  it 
is,  or  recrystalized. 

The  development  and  redevelopment  should 
be  clone  over  a  tub  or  barrel.  The  mud  which 
collects  at  the  bottom,  contains  a  large  amount 
of  metallic  silver. 

The  washings  of  the  prints  before  toning, 
are  all  poured  into  a  tub  or  barrel,  in  which 
are  put  some  plates  of  copper.  The  next  day 
all  the  silver  is  precipitated,  and  the  clear 
liquid  can  be  drawn  off. 

The  scraps  of  silvered  paper,  which  have 
not  passed  through  the  hyposulphite,  the  blot 
ting  paper  used  to  absorb  the  drainings  in 
the  plate-holder,  the  filters  used  for  filtering 
silver  solutions,  etc.,  are  burned  in  an  iron 
pot,  standing  in  the  open  air.  The  ashes  con 
tain  chloride  and  metallic  silver. 

The  cyanide  and  hyposulphite  are  deprived 
of  their  silver  by  plates  of  copper.  It  takes 
two  or  three  days  to  precipitate  all  the  silver 
the  solution  contains.    The  precipitate  is  me- 


253 


tallic  silver  mixed  with  a  small  quantity  of 
sulphide.  The  clear  hyposulphite  can  be 
used  over  again  to  fix  negatives. 

The  metallic  silver,  ashes,  etc.,  may  be  put 
together  and  given  to  the  refiner.  When  this 
is  done,  care  should  be  take  to  wash  perfectly 
the  precipitate  of  the  hyposulphite  solution. 
It  is  best,  however,  to  keep  this  precipitate 
apart,  as  it  may,  sometimes,  contain  a  great 
deal  of  sulphide,  which  is  more  difficult  to 
reduce  to  the  metallic  state  than  other  silver 
compounds. 

The  different  recommendations  we  make 
here,  are  those  described  by  Messrs.  Davanne 
and  Grirard,  who  have  made  the  reducing  of 
wastes  a  special  study. 

We  would  not  recommend  to  the  photo- 
grapher to  reduce  his  wastes  himself;  we 
consider  it  his  interest  to  leave  this  to  the 
chemist  or  refiner,  who  have  the  necessary 
practical  knowledge,  and  possess  the  necessary 
apparatus  to  accomplish  this  end.  We  will, 
however,  briefly  describe  the  different  pro- 
cesses. 

Metallic  silver,  precipitated  by  means  of 
copper,  may,  as  we  have  already  mentioned, 
be  directly  transformed  into  nitrate  of  silver, 
by  dissolving  in  nitric  acid.  Chemists,  how- 
ever, prefer  to  melt  the  silver  before  convert- 
ing it  again  into  nitrate.  This  is  done  as 
follows : 

The  silver  powder,  washed  and  dried,  is 


254 


mixed  in  a  mortar  with  half  its  weight  of 
fused  and  pulverized  borax,  and  one-fourth 
of  its  weight  of  fused  and  pulverized  nitre. 
A  crucible  is  then  put  in  a  good  furnace,  and 
made  red-hot,  when  the  mixture  is  thrown 
into  it,  little  by  little.  When  the  ebullition 
has  ceased,  the  fire  is  increased,  and  the  cru- 
cible is  kept  white-hot  for  fifteen  or  twenty 
minutes,  after  which  it  is  left  to  cool,  when 
it  must  be  broken  to  remove  the  button  of 
silver. 

The  waste  resulting  from  development  and 
redevelopment,  can  be  mixed  with  the  silver 
precipitated  by  means  of  copper,  when  this  is 
melted,  or  if  this  is  transformed  into  nitrate, 
without  being  previously  melted,  it  is  added 
to  the  ashes  of  the  burned  paper.  The  ashes 
of  burned  paper  are  mixed  with  half  their 
weight  of  dry  carbonate  of  soda,  and  one- 
fourth  of  their  weight  of  quartz  sand,  and 
reduced  in  a  crucible  in  the  manner  described 
before. 

If  the  metallic  silver  and  the  ashes  are  put 
together,  the  whole  mass  is  fused  with  car- 
bonate of  soda,  nitre,  and  sand. 

When  the  precipitates  contain  sulphide  of 
silver,  the  reduction  is  more  difficult.  It  is 
necessary,  then,  to  keep  the  mass  at  a  white- 
heat  for  at  least  an  hour. 

The  method  generally  used  by  photograph- 
ers is,  to  precipitate  their  washings  by  means 
of  salt.    This  method  is  good  enough  when 


255 


the  silver  solution  is  of  a  certain  strength,  but 
when  the  water  contains  but  a  small  amount 
of  silver,  quite  a  quantity  is  lost  by  the  chloride 
not  all  settling  to  the  bottom,  or  by  dissolving 
in  an  excess  of  salt.  The  use  of  copper,  in- 
stead of  chloride,  secures  the  precipitation  of 
all  the  silver  the  water  contains. 

The  process  of  precipitating  the  silver  out 
of  the  hyposulphite  solution,  by  means  of 
sulphide  of  potassium,  is  also  inferior  to  the 
one  we  describe  above.  The  precipitate  ob- 
tained is  sulphide  of  silver  mixed  with  sul- 
phur, and  before  it  can  be  reduced  in  the 
crucible,  which  itself  is  an  operation  attended 
with  many  difficulties  and  accidents,  it  has  to 
be  roasted;  that  is,  the  sulphur  has  to  be 
burned  up  by  heating  the  precipitate  on  an 
iron  plate. 

To  save  the  gold  of  old  toning  baths,  acidify 
them  with  hydrochloric  acid,  and  add  a  small 
quantity  of  a  solution  of  iron.  This  will  pre- 
cipitate the  gold  in  the  metallic  state.  Sep- 
arate the  precipitate  by  filtration,  wash  well 
and  redissolve  in  nitro-hydrochloric  acid.  An 
acid  solution  of  chloride  of  gold  is  then  ob- 
tained, which  is  neutralized  by  leaving  it  in 
contact  with  a  piece  of  chalk.  When  all 
effervescence  ceases,  and  the  solution  is  neutral 
to  test-paper,  filter,  and  use  it  for  toning. 


256 


CHAPTER  XLVI. 

Removing  Stains  from  the  Skin,  Linen,  etc. 

Stains  of  nitrate  of  silver  can  be  easily 
removed  from  linen,  by  the  application  of  a 
saturated  solution  of  hypochlorite  of  lime, 
(chloride  of  lime.)  This  requires  from  one 
to  five  minutes.  In  this  case,  the  metallic 
silver  is  changed  into  white  chloride. 

Instead  of  chloride  of  lime,  the  following 
solution  can  be  used: 


Cyanide  of  Potassium 

Water  

Dry  Iodine  


1  ounce. 
16  ounces,  fluid. 
1  drachm. 


This  solution  is  applied  with  a  small  brush. 
It  removes  the  stains  in  a  few  seconds. 

Hyposulphite  of  soda  may  be  substituted  to 
the  cyanide  of  potassium,  in  which  case,  the 
stains  will  not  be  removed  so  quickly.  Sub- 
sequent applications  of  tincture  of  iodine  and 
cyanide  of  potassium,  or  hyposulphite  of  soda, 
will  also  produce  the  same  effect. 

The  same  substances  which  remove  the 
stains  from  linen  will  remove  them  from  the 
skin. 

When  the  color  of  the  fabric  is  liable  to  be 
injured  by  the  chloride  of  lime,  or  cyanide  of 


257 


potassium,  the  solution  of  iodine  in  hyposul- 
phite of  soda  is  preferable. 

Iron  stains  are  removed  by  the  application 
of  a  weak  solution  of  oxalic  acid. 

Stains  of  collodion  will  dissolve  in  a  mixture 
of  ether  and  alcohol. 

Iodine,  cyanide  of  potassium,  oxalic  acid, 
and  chloride  of  lime,  having  a  corrosive  action, 
these  substances  should  be  removed  by  rins- 
ing the  linen  in  clean  water,  as  soon  as  their 
full  effect  is  produced. 


22 


HOLMES,  BOOTH  &  HAYDENS, 

49  Chambers  Street,  New  Yorlc, 
(Opposite  New  City  Hall,) 
MANUFACTURERS,  IMPORTERS,  AND  DEALERS 

 IN  

PHOTOGRAPHIC  MATERIALS 

OF  EVERY  DESCRIPTION. 

Dealers  and  Artists  will  always  find  at  onr  Establishment 
A  LARGE  AND  WELL  ASSORTED  STOCK, 

ZEUVCIBIR^CIILTG- 

CASES,  MATTINGS,  PRESERVERS,  CARD-BOARDS,  MOUNT'S  PAPER  MATS,  ETC. 

Every  article  required  by  the  dealer,  or  amateur,  will  always  be 
of  the  latest  and  best  designs  and  qualities. 

PARTICULAR  ATTENTION  GIVEN  TO  THE  SELECTION  OF 

SAXI  PHOTOCRAPH.IG  FAFIE. 

Our  arrangements  for  procuring  this  article  are  such,  that  we 
shall  always  be  supplied  with  the  best  quality 
that  the  foreign  market  affords. 

"We  are  constantly  receiving  from  abroad  invoices  of 

PORCELAIN  WARE,  EVAPORATING  DISHES,  GLASS,  FILTERING  PAPER,  ETC., 

which  we  shall  always  sell  as  low  as  the  rates  of  Exchange  will 

allow. 

HOLMES,  BOOTH  &  HAYDENS' 

Celebrated  Cameras, 

are  guaranteed  equal,  in  every  respect,  to  the  best  of  any  other 
manufacturer,  either  foreign  or  domestic.    We  can 

furnish  Cameras  made  expressly  for  the 
O^R/TJES   I>JE   VISITE  PICTURES, 

and  carefully  matched  in  sets  of  two  or  four.    Also,  one-ninth 
size  tubes,  for  Ferrotype  work. 

HOLMES,  BOOTH  &' HAYDENS' 

EUHEKA  PLATES 

are,  also,  deserving  of  special  notice.  These  Plates  are  manufac- 
tured by  us,  under  the  direction  of  a  party  who  has  had  more  than 
twenty-five  years  experience  in  this  branch,  and  we  warrant  every 
box  to  be  uniform  and  perfect. 

HOLMES,  BOOTH  &  HAYDENS, 

No.  49  Chambers  Street,  New  York. 
MANUFACTORY  AT  WATERBURY,  CONN, 


SCOVILL  MANUFACTURING  CO. 


IMPORTERS  AND  DEALERS, 

Manufactory,     \    IS  a.  <L  Beekman  St., 
WATERBURY,  CONN.  I  NEW  YORK. 

OFFER  TO  THE  TRADE,  ARTISTS,  AND  THE  AMATEUR, 


A  COMPLETE  ASSORTMENT  OF 


Mostly  of  their  own  manufacture,  but  all  of  the  best  known  makers,  embracing 

Apparatus,                 Cases,  Glass  of  all  Kinds, 

Chemicals.                  Frames,  Photographic  Paper, 

Preservers,                 Mattings,  Photographic  Albums,  etc. 

AGENTS  FOR 

Harrison  &  Schnitzer's  Patented  Globe  Lenses, 

C.  C.  Harrison's  Renowned  Portrait  Cameras, 
Whitney's  Patent  Printing  Frame, 

Tagliabue's  Actino-Hydrometers, 

Mowry's  Photographic  Presses, 

Campbell's  "Verms"  Plates, 
We  would  respectfully  invite  attention  to  our  extensive 

STOCK  OF  CASSS, 

manufactured  by  ourselves,  including 
MANILLA,  LEATHER,  CUPID,  JEWEL,  EANCY, 

AND  THE 

"UNRIVALED"  UNION  CASES,  FRAMES,  AND  TRAYS, 

now  manufactured  by  us  in  increased  variety,  and  to  which  all  parties  concede 
superior  excellence  in  design  and  workmanship. 

EXCELSIOR  ALBUMENIZED  PAPER, 
prepared  from  the  best  saxe  and  rive  papers,  by  one  of  the  most  experienced 
parties  in  the  country,  and  guaranteed  to  give  satisfaction 
equal  to  any  other  in  the  market. 

Plain  Saxe  and  Rive  Paper  furnished  to  Albumenizers  at  the  Lowest  Importation  Rates. 

Pure  Nitrate  of  Silver,  Chloride  of  Gold,  and  Positive  and  Negative 
Collodion,  of  the  best  Qualities. 

Card  Camera  Boxes,  (with  and  without  Ferreo.  Attachment,)  Card 
Mounts,  Card  Board,  Paper  Mats,  Focussing  Glasses, 
Backgrounds,  etc.,  etc. 

CARD  &  FERROTYPE  CAMERAS  FURNISHED,  MATCHED,  IN  SETS  FROM  TWO  TO  SIX  TUBES. 

JS®" Orders  attended  to  with  care  and  dispatch,  and  expressed  (or  sent 
otherwise)  to  any  part  of  the  country.  Address 

SCOVILL  MANUFACTURING  COMPANY, 

2Vo»  4  Beekman  St.,  New  York. 


BENJ.  FRENCH  &  CO. 

IMPORTERS  AND  SOLE  AGENTS  IN  THE  UNITED  STATES  FOR 
THE  CELEBRATED 

VOIGTLANDER  &  SON  CAMERAS! 

 ALSO  

THE  JAMIN  CAMERAS. 

We  can  furnish  the  1-4,  1-3,  1-2,  and  3-4  Tubes  and  Lenses  in  sets  of  two  or 
four,  precisely  matched,  of  same  length  of  focus.  The  Voigtlander  &  Son's 
Tubes  and  Lenses  are  much  shorter  focus,  and  work  much  quicker,  and  have 
more  depth  of  focus  than  any  other  instrument  in  use.  The  great  reputation 
these  instruments  have  throughout  the  world,  needs  no  recommendation  from 
us.   We  warrant  every  one  to  give  entire  satisfaction. 

WE  KEEP  CONSTANTLY  ON  HAND  A  LARGE  STOCK  OF 

SAXE'S  AND  RIVES'  POSITIVE  PAPER. 


ALBUMEN  PAPER  OF  VARIOUS  KINDS  AND  OF  SUPERIOR  QUALITY. 
Photographic  Albums  in  Great  Variety  of  Styles  and  Bindings. 

Gilt,  Imitation  Rosewood,  and  Black  Walnut  Frames,  in  Great  Variety  of  Styles. 
ENGLISH,  FRENCh7gERWAN,^ND  AMERICAN  GLASS, 

For  Negatives,  3-4  White  Plate ;  also,  1-9, 1-6, 1-4, 1-2,  and  4-4  White  Porcelain 
Glass.   Also,  every  description  of  Goods  used  in  the  Photographic 
business,  which  will  be  sold  at  all  times  at  the  lowest 
PRICES. 

IMPROVED  PHOTOGRAPHIC  BACKGROUND, 

MANUFACTURED  BY  PETER  FALES,  NEW  BEDFORD,  MASSACHUSETTS. 

BE N J  FIIE NC H  &  CO. 

INT  o  •  159   W  asliington  Street, 

SOLE  AGENTS  FOR  THE  UNITED  STATES. 

PATENT  APPLIP^D  FOR. 

The  above  Backgrounds  have  the  appearance  of  unfinished  cloth,  which 
gives  a  very  soft  effect;  are  very  durable,  not  liable  to  show  indentures  or 
marks  from  rubbing  against  it — so  prominent  faults  in  the  painted  Back- 
grounds. We  shall  keep  constantly  on  hand  the  different  sizes,  varying  from 
6x7%  to  7%xl0  feet,  in  all  desirable  colors  and  shades.  Larger  sizes  made  to 
order.  The  Backgrounds  come  on  wood  rolls,  packed  in  neat  boxes,  and  in 
condition  to  send  any  distance.  Samples  sent  by  mail. 

Price,  25  Cents  per  Square  Foot. 


WESTERN  HEAD-QUARTERS 

—  FOR  

PHOTOGRAPHIC  AND  AMBROTYPE  STOCK. 


L.  B.  DARLING, 

2To.  1 00  West  Fifth  Street,  Cincinnati,  O. 
MANUFACTURER,  IMPORTER,  AND  DEALER 

IN  EVERY  KIND  AND  VARIETY  OF 

GOODS  AND  CHEMICALS  REQUIRED  BY  OPERATORS. 


The  following  articles,  of  my  own  manufacture,  are  not  excelled  by  any  in 

the  United  States : 

Photographic  Chemicals, 

Negative  Collodion, 

Chloride  of  Gold, 

Nitrate  of  Silver, 

Albumen  Paper. 

Those  who  have  had  trouble  in  getting  a  good  reliable  Collodion 
are  invited  to  send  for 

DARLING'S  NEGATIVE  COLLODION, 

and  they  will  have  no  further  difficulty.    Large  buyers  are  par- 
ticularly invited  to  look  at  my  stocky  or  get  prices 
before  purchasing.    I  am  Agent  for 

HOTiTWiTS  fliTSTAL  YABHI8H, 

the  best  now  in  the  market.    Those  who  have  used  it  will  have 

no  other. 

DRIE8  WITHOUT  IIIlJAlT. 

ALSO,  SOLE  WESTERN  AGENT  FOR 

MOUNTFORT'S  CALCINED  ROTTEN  STONE, 

—  FOR  — 

CLEANING  AND  POLISHING  GLASS. 

There  is  nothing  better  for  the  purpose. 

ARTISTS'  WASTES  REFINED  ON  THE  BEST  TERMS. 

ALL  ORDERS  FILLED  THE  DAY  THEY  ARE  RECEIVED  AND  GOODS  CAREFULLY  SELECTED. 

Xj-  IB.  DARLING, 

(Box  £313,) 

W.  D,  GATCHEL,  Manager.  Cincinnati,  Ohio. 


SOUVEETIilZN-Q-  NEWI 


IMPORTANT  TO  PHOTOGRAPHERS. 


 FOR  

AMBKOTYPES,  NEGATIVES,  AND  MELAINOTTPES. 

JVo  Heat  Necessary  in  Drying* 

The  only  perfectly  reliable  Varnish  in  use,  and  which  is  sup- 
ported and  recommended  by  the  most  eminent 
Photographers  in  this  Country. 


It  contains  ingredients  never  before  used  in  Varnishes,  and 
possesses  the  following  merits  over  every  other  brand : 

It  is  used  without  heat,  thereby  saving  the  cost  of  burning 
alcohol. 

It  never  chills  if  the  plate  is  dry. 

It  is  perfectly  transparent,  and  does  not  diminish  the  intensity 
of  the  negative. 

It  will  not  stick  to  the  paper  or  become  soft  in  printing. 

It  is  equally  good  for  positives  or  negatives. 

Bichloride  Mercury  should  not  be  used  in  strengthening 
the  negative. 

ALSO, 

MOUlsTTFORT'S 

CALCINED  ROTTEN  STONE, 

MAW UFACTUEED  FROM 

Superior  English  Rotten  Stone, 

Selected  expressly  for  the  purpose.  It  is  warranted  perfectly  free 
from  grit,  and  all  foreign  substances,  and  will  be  found  to  pos- 
sess qualities  superior  to  any  preparation  of  the  kind  in  use ;  it 
will  clean  very  quick,  yet  perfectly  free  from  scratches. 

L.  B.  DARLING, 

Manufacturer,  Importer  and  Dealer  in  Photographic  Goods, 
100  West  Fifth  Street 9  Cincinnati,  Ohio* 
Sole  Agent  for  the  Western  States, 
W.  D.  CATCHEL,  Manager  at  Cincinnati. 


BETVZITVE  VARNISH 
IFOIEt  WEG-ATIVES, 

PREPARED  BY 

CHARLES  WALDACK, 

26  West  Fourth  Street, 
CINCINNATI,  OHIO. 


This  Varnish  Dries  without  Heat  in  a  few  Seconds, 

And  gives  a  very  hard  surface,  perfectly  protecting-  the  Neg- 
ative, and  not  liable  to  crack  or  split*   It  does  not 
reduce  the  intensity  of  Negatives  except  when 
these  have  been  strengthened  with 
mercury,  ( a  method  now  gen- 
erally abandoned.) 

THE  COLOR  OF  THE 

Is  Brown  when  in  the  Bottle,  but  it  gives  a  Colorless  Film  on  the  Negative. 

N.  B. — When  a  collodion  is  used  giving  a  very  porous  film,  or  when  the 
Negative  has  been  much  strengthened  with  mercury,  it  is  necessary  to  coat 
the  surface  with  a  solution  of  one  ounce  of  gum-arabic  in  twelve  ounces 
of  water,  before  applying  the  Varnish.  If  this  not  be  done,  the  half  tone 
of  the  Negative  may  be  made  more  transparent,  while,  when  the  deposit 
is  the  thickest,  the  original  intensity  of  the  dried  film  persists,  thus  pro- 
ducing a  mottled  effect,  which  makes  the  Negative  unfit  for  printing.  All 
varnishes,  whether  made  with  alcohol,  benzine,  or  chloroform,  will  produce 
this,  provided  they  give  a  film  possessing  sufficient  body  to  protect  the  Neg- 
ative. Very  thin  varnishes  are  free  from  this  defect,  but  they  leave  the 
Negative  hardly  less  tender  and  liable  to  be  scratched  than  if  only  gum- 
water  was  used. 

FOR  8ALE  BY 

CHAELES  WALDACK, 

No.  28  Vest  Pourtli  Street,  Cincinnati,  Ohio, 

AND  BY 

Dealers  in  Photographic  Materials  Generally. 


PHOTOGKAPHERS' 

GOLD  AND  SILVER  WASTE 

CAREFULLY  REFINED, 

And  the  Product  returned  in  Nitrate  of  Silver  and  Chlor.  of  Gold 

TERMS :  -------    Twenty  Per  Cent. 

FREIGHT  AND  EXPRESS  CHARGES  PAID  BOTH  WAYS, 
fi&-  send  for  a  Circular  giving  full  Directions  for  Collecting  Wastes, 
Address 

"W_  -A—  STEWART, 

North-  West  Cor.  Seventh  &  IAnn, 

CINCINNATI,  OHIO. 


PLAIN,  POSITIVE,  AND  NEGATIVE 

COLLODIONS 

Prepared  from  the  Best  Materials  by 

CHARLES  WALDACK, 

NO.  28  WEST  FOURTH  STREET, 
CINCINNATI,  O. 

FOR  SALE  BY  DEALERS  IN  PHOTOGRAPHIC  MA- 
TERIALS GENERALLY. 

23 


SHIVE'S  PATENT  PORTABLE  HELIOTROPIC  SOLAR  CAMERA. 

This  instrument  is,  perhaps,  one  of  the  most  important  to  the  Photographer 
•Ter  invented  for  his  use.   Its  advantages  are : 

It  supplies  the  place  of  large  instruments,  therehy  obviating  the  trouble  and 
expense  of  making  large  negatives,  and  keeping  up  large  baths. 

From  a  fourth  or  half  size  negative,  it  will  make  a  four-fourth,  life  size,  or, 
indeed,  any  size  print  that  may  be  desired,  as  sharp  and  as  deep-toned  as  a 
contact  print.  It  is,  in  every  sense,  a  Solar  Camera,  does  not  require  a  dark 
room,  but  can  be  operated  under  a  skylight,  at  a  window,  out  of  doors,  or 

*  ^lace  where  the  sun's  rays  can  reach  it. 


It  is  complete  in  itself,  having  every  appliance  to  print  every  style  of  picture 
that  can  be  printed  by  any  other  arrangement.  It  prints  by  the  direct  rays  of 
the  sun,  which  gives  it  power  nearly  three  to  one  over  refected  light.  It  dis- 
penses with  all  reflectors,  and  trappings  and  machinery  for  operating  them, 
and  is  furnished  at  one-half  the  cost  of  a  reflector  apparatus,  the  power  being 
equal.  It  is  so  simple  in  its  construction  and  operation  that  the  most  inex- 
perienced can  work  it  successfully. 

For  particulars  of  Price,  Sizes,  etc.,  address  the  manufacturer, 

JOHN   II.  SIMMONS, 
MANUFACTURES,  IMPORTER,  AND  DEALER 

IN  EVERT  DESCRIPTION  OP 

fkotogragMe  Apparatus  a&$  Materials, 

607  Chestnut  Street,  TMladelpMa,  Tenn. 


Stnpv'm  $xt\uh  ®%pU\  WmuhU. 


THE  CRYSTAL  VARNISH 

Has  been  in  use  for  more  than  Seven  Years,  and  no  Varnish  has  been  fonnd  to  excel  it  for  Positive* 

PICTURES  FINISHED  WITH  THE 

IFIELEIIXrOEC    CRYSTAL  "V-A.KlSriSHC 

never  change  from  exposure  to  light.  This  can  be  said  of  no  other,  more 
particularly  the  Spirit  Varnish,  which  will,  in  time,  cause  pictures  to 
change  to  a  brownish  hue,  especially  if  made  on  an  iron  plate. 

The  Crystal  Varnish  is  Warranted  Superior  to  all  others  in  use  for  Positives  on  Glass  or  Iron. 

WBITE  FOR  MAGGINFS  FRENCH  CRYSTAL  VARNISH 

Kone  Genuine  unless  Signed  «T.  A.  Magginl. 

POE  SALE  BY  ALL  AMBEOTYE  AND  PHOTOGEAPH  STOCK  DEALEES, 


JOHN  B.  PURDY, 

(LATE  WITH  ASHE,  DAYTON  &  CO.) 

PHOTOGRAPHIC  BACKGROUNDS, 

A.T  REDUCED  PRICES. 


Plain,  (Equal  to  any  in  the  Market,  and  TWENTY-FIVE  PEE  CENT, 
CHEAPEB,)  Landscapes,  Military,  Naval,  Parlor,  Hall,  Library, 
Park  Scenery,  Imitation  Columns,  Eails,  Pedestals, 
Window  Scenes,  Bine  Eeflectors,  etc. 

OLD  BACKGROUNDS  REPAINTED, 

EQUAL  TO  NEW. 

I  am  now  happy  to  inform  Photographers  that  I  have  succeeded  in  an  object 
heretofore  pronounced  by  background-makers  as  impossible;  namely,  the 
repainting  of  old  Backgrounds.  Any  Photographer  having  an  old  ground,  (oil 
and  flock  excepted,)  if  not  torn,  can  have  any  tint  or  design  repainted  on  it,  at  the 
rate  of  ten  cents  per  foot,  for  plain,  or  a  proportionate  price  for  scenery,  ac- 
cording to  the  amount  of  labor  in  the  execution.  Expenses  paid  one  way. 

J-OHCIST   33.  IPTTRID^r, 
52  Franklbi  Street,  near  Broadway,  JK  F. 


HARRISON  CAMERA  FACTORY. 

Office,  458  JBroaclivay,  New  York. 


PORTRAIT  TUBES, 

 AND  — 

0.  0.  HAEEISOFS  AND  J.  SOHJTITZEB'S 

FATIITIB  (SJk©BI  MISSIS. 


The  "  C.  C.  Harrison's"  Portrait  Tubes,  which,  for  the  past  sixteen  years, 
have  been  so  favorably  known,  and  are  now  almost  exclusively  used  in  the 
first-class  Photographic  Galleries  in  the  Union,  are  being  made  in  larger 
quantities,  and,  if  possible,  in  still  greater  excellence  than  ever. 

Tlieix-  Ilig-lx  Character  will  l>e  Sustained. 
Not  an  instrument  will  be  sent  out  that  Mr.  Harrison,  by  the  severest  tests, 
has  not  found  perfect.   Every  tube  is  warranted  to  be  thus,  and  to  give  entire 
satisfaction.  The 

C.  C.  HARRISON  &  J.  SCHNITZER 
PATENTED    GLOBE  LENSES, 

For  taking  Landscapes  and  Architectural  views,  and  for  copying  Prints,  Maps, 
Drawings,  etc.,  far  excel  all  Lenses  heretofore  introduced  for  these  pur- 
poses.  The  advantages  claimed  for  them  are : 

First.— They  will  embrace  almost  twice  as  much  subject  upon  the  same 
»zed  plate  as  that  of  any  other  combination. 

Second. — Their  great  depth  of  focus — objects  near  by  and  distant  being 
equally  sharp  and  well  defined. 

Third. — An  equal  illumination  and  perfect  definition  of  the  whole  field. 

Fourth. — The  property  of  rapid  working,  with  very  small  aperture. 

Fifth. — The  heretofore  unattainable,  but  so  long  sought  for,  quality  of  pro- 
ducing, when  used  in  copying  negatives,  perfect  in  definition  and  entirely  free 
from  distortion. 

All  these  qualities  we  guarantee  these  Lenses  to  possess,  and  any  pur- 
chaser, who,  after  a  month's  trial,  is  not  satisfied,  is  at  liberty  to  return  ttie 
Lens  to  us,  and  receive  the  amount  paid. 

Our  Portrait  Tubes  and  Globe  Lenses  may  be  obtained  from  all  the  stock- 
dealers  in  this  and  other  cities. 
Orders  should  be  addressed  to 

NELSON  WRIGHT, 

458  BROADWAY,  STEW  YOEK. 


JOHN  STOCK  &  CO, 


207  and  209  Center  Street. 

OFFICE,  S-A-3yCFXiE,  SALESROOM, 

458  Broadway,  Corner  Grand  Street,  New  York. 


The  Subscribers,  owing  to  the  great  and  increasing  demand  for  their  Photo- 
graphic work,  have  been  compelled  to  change  their  plan  of  business,  and  have 
taken  extensive  Rooms,  with  ample  steam  power,  in  Center  street;  and,  with 
machinery  made  expressly  for  and  exactly  adapted  to  their  work,  they  wiU 
hereafter  be  able  to  supply  the  demand,  no  matter  how  large,  with  Camera 
Boxes,  Baths,  Stands,  Printing  Frames,  etc.,  of  unequaled  quality. 

They  take  pleasure  in  informing  their  friends  and  the  public,  that  they  have 
made  an  arrangement  with  Mr.  NELSON  WRIGHT,  (Harrison  Camera  Fac- 
tory,) by  which  they  will  be  relieved  from  the  selling  and  other  business 
operations,  and  devote  their  time  wholly  to  manufacturing.  Soliciting  the 
continuance  of  the  public  favor,  which  has  heretofore  been  so  liberally  be- 
stowed, we  are,      Yours  respectfully,  etc.,  JOHN  STOCK  &  CO. 

The  undersigned  will  be  happy  to  show  samples,  and  take  orders  for 
JO  11?*  8TOC  I£  «&  CO.'H 
BOXES,  BATHS,  STANDS,  AND  OTHER,  PHOTOGRAPHIC  APPARATUS. 

With  very  great  facilities  in  machinery  and  power,  and  with  large  supplies 
of  superior  seasoned  timber  and  other  materials,  it  is  hoped  orders  will  be 
filled  with  a  promptness  that  will  satisfy  every  one.  Prices  will  be  made  as 
low  as  possible,  kept  regular,  and  no  deviation  made.  Stock-dealers  will  be 
allowed  a  liberal  discount.  The  especial  attention  of  amateurs  and  of  all 
artists,  who  appreciate  and  wish  to  possess  perfect-working  apparatus,  is  called 
to  the  New  Patented  Improved  Camera  Boxes,  which  consist  of  the  following : 

THE  IMPERIAL  CAMERA, 

FOR  TAKING  PICTURES   BOTH  IN  THE  GALLERY  AND  IN  THE  FIELD. 


UNIVERSAL  CAMERA, 

FOR  ALL  KINDS  OF  WORK— SINGLE  PICTURES,  TWO  OR  FOUR  ON  A  PLATE,  AND  FOB 

COPYING. 


IMPERIAL  FOLDING  CAMERA, 

FOR  COPYING;   ADAPTED  FOR  FIELD  AND  GALLERY  USE. 


PATENT  ARTISTS'  CAMERA. 


STEREOSCOPIC  CAMERAS, 

DOUBLE  AND  SINGLE,  WITH  THE  PATENT  DRY-BOX. 


CAMERA  TABLE, 

THE  MOST  PERFECT  AND  CONVENIENT  ARTICLE  KNOWN. 


PATENT  GLASS  BATH, 

ESTEEMED  THE  ONLY  PERFECT  SILVER  BATH  EVER  INTRODUCED. 


An  Illustrated  Pamphlet,  with  Prices,  will  soon  be  issued,  and  will  be  sent 

to  any  one  wishing  it, 
ALL  ORDERS  SHOULD  BE  ADDRESSED  TO 

NELSON  WRIGHT, 

458  Broadway,  Comer  Grand  Street,  New  York, 


HERMAN  ROBTTGER, 

NO.  402  LIBB&RY  STKEET. 
PHILADELPHIA,  PENN. 


MANUFACTURER  OF 


TELESCOPES,  ETC. 


09 

Pi 
O 

02 


PRICE-LIST   OF  CAMERAS. 

Mammoth  Size,     Lenses  6  J-  by  6}  inches  diameter, 


$350  00 

5J  by  5:}     »  "         200  00 
4J  by  4£     "           "  160  00 
3£  by  Sf     "           "  120  00 
H  by  3J     «          "  90  00 
2|  by  2|     «           «           45  00 
1J  by  If     «           "  30  00 
2J  by  1J     «           «           45  00 
»     3   by  2\     «           «  70  00 
Twin  Tubes  with  Center  Stops,  for  "  Cartes  de  Visite,"           90  00 
Triplets,  (an  improved  instrument  for  landscapes,  copy- 
ing, etc.)  -      -     30  00  to  160  00 

Solar  Camera  Tube,     -       -  -      -      -      -       45  00 

LENSES  FOR  SOLAR  CAMERAS. 
Piano-Convex  Lens,  5  inch,  diameter,  10  to  12  inch,  focus,  $  8  00 


Extra  Double  Whole, 
Double  Whole, 
Extra  Whole, 
Whole, 
Half, 
Quarter, 
Orthoscopic  Tube, 


6 
7 
8 
9 

10 
11 


10  to  15 
10  to  18 
12  to  18 
19  to  25 
22  to  25 
22  to  30 


9  00 
12  00 
15  00 
20  00 
30  00 
35  00 


Larger  Lenses  furnished  upon  special  orders. 
TELESCOPES. 
With  Object  Glass  2£  inches  aperture  and  Stand, 

3  " 

4  « 

5  « 

6  " 

7  " 

8  " 

Object  Glasses  for  Mathematical  Instruments,  etc.*  furnished  any  size  upon  orders 


$100  00 
160  00 
275  00 
420  00 
650  00 
1000  00 
1500  00 


PORTABLE  DARK-ROOM, 

FOR 

@iTi©@@I  WORK, 


This  Dark-room,  when  put  up  for  use,  leaves 
ample  space  for  operating.  It  holds  the  bath, 
collodion,  developing  solutions,  etc.,  and  is 
fitted  with  a  sink  and  waste-pipe  to  carry  off 
the  washings.  When  folded  up,  it  can  be 
easily  carried  in  one  hand.  It  can  be  put  up 
ready  for  use  in  two  minutes.  It  is  made  of 
such  a  size  that  plates  10  by  12  inches  can  be 
easily  operated  upon.  It  is  supplied  with 
water  by  means  of  an  India-rubber  bag,  which 
is  suspended  to  some  object  near  by. 

CHARLES  "W-A.XjI>-A.OEC3 
JSo.  28  West  Fourth  Street, 
CINCINNATI,  O. 


FOB 


OUT-DOOR  WORK  AND  COPYING. 


This  Camera  possesses  all  the  requirements  for  out-door 
work.  It  is  light,  compact,  portable,  and  strong.  It  is 
constructed  so  that  the  lens  slides  up  or  down,  thus  avoid- 
ing the  necessity  of  tilting  in  case  it  is  wished  to  include 
more  sky  or  foreground.  It  can  be  used  in  its  width  or 
in  its  length,  according  to  the  nature  of  the  subject.  As 
it  extends  two  or  three  feet,  according  to  its  size,  it  can  be 
made  very  useful  as  a  copying  and  enlarging  Camera. 
When  used  for  that  purpose,  it  is  fastened  to  a  board  con- 
structed so  that  the  picture  to  be  copied  can  be  raiseil  or 
lowered,  and  set  nearer  to  the  Camera  or  further  from  it. 
The  Camera  and  plateholder,  when  folded  up  for  traveling, 
form  a  package  which  can  be  easily  carried  in  one  hand. 

When  used-  in  the  field,  the  Camera  is  supported  on  a 
light  and  solid  tripod  stand. 

The  following  sizes  are  constructed : 

4f  by  8   inches,  (Binocular  Stereoscopic  Camera.) 

6£  by  Si  « 

8  by  10  " 
10  by  12  «« 
12  by  15  " 
14  by  17  " 

The  Binocular  Camera  is  made  either  for  one  or  two 
lenses.  When  one  lens  is  used,  it  is  attached  so  that  it 
can  be  moved  from  right  to  left,  or  vice  versa.  This 
Camera  is  also  accompanied  with  a  platform,  which  is  used 
when  the  two  pictures  have  to  be  made  from  two  points, 
wider  apart  than  the  distance  between  the  two  lenses. 

FOR.  SALE  BY 

CHAELES  WALDACK, 
JVb.  28  West  Fourth  Street, 
CINCXBTNATI,  O. 


The  Philadelphia  Photographer, 

A  MONTHLY  JOURNAL,  DEVOTED  TO  THE  PHOTOGRAPHIC  ART. 


,  In  soliciting  patronage  for  the  Second  Volume  of  this  useful  Magazine,  the 
Publishers  would  call  the  attention  of  Photographers,  Artists,  Amateurs,  and 
all  lovers  of  the  art  to  the  following 

TESTIMONIALS  : 

"I  have  read  with  much  interest  the  Numbers  of  the  Philadelphia  Photographer, 
and  hope  that  it  may  prosper.  I  shall  be  glad  to  contribute  to  its  pages."— Prof,  Oyden 
N.  Rood. 

"The  contents  arc  of  an  interesting  nature,  and  to  all  photographers  will  be  useful  and 
valuable  ;  for  they  are  evidently  the  productions  of  clear-headed,  practical  men.  Our 
cotemporary  promises  to  be  a  valuable  acquisition  to  the  cause  of  progressive  science." — 
Scientific  American. 

"It  will  supply  a  want  experienced  by  the  profession  as  well  as  by  amateurs.  We  per- 
ceive it  has  been  indorsed  by  some  leading  Photographic  journals  in  England,  Paris,  and 
Brussels."— Dr.  R.  She  I  ton  Mackenzie. 

"  Of  this  young  Review,  organ  of  one  of  the  most  justly  reputed  Photographic  Societies, 
it  may  be  said  that  no  prospectus  was  ever  more  faithfully  carried  out  than  it  has  been. 
It  is  a  rich  and  valuable  publication,  both  as  respects  its  execution  and  in  a  scientific 
point  of  view." — Bulletin  Beige. 

"  The  frontispiece  is  a  very  successful  photograph,  not  having  a  single  defect,  and  is 
well  worth  twice  the  price  of  the  Number  as  a  specimen  of  art  in  respect  to  sharpness  and 
toning." — Prof.  Towler,  Editor  Humphreys  Journal  of  Photography . 

"  I  have  read  a  great  part  of  every  Number,  and  with  great  interest  and  profit;  .... 
almost  ready  to  send  you  a  negative  of  my  own  make  as  a  candidate  for  your  frontis- 
piece/'— Prof.  Oliver  Wendell  Holmes. 

"The  only  Photographic  Journal  in  the  world,  giving  a  Photograph  in  each  number,  is 
the  Philadelphia  Photographer,  an  excellent  Journal,  ably  conducted,  and  beautifully 
printed." — Photographic  News. 

No  pains  will  be  spared  by  the  Publishers  to  keep  up  the  appearance  and 
interest  of  the  Journal  in  a  way  even  surpassing  the  last  volume. 

The  coming  volume  will  be  copiously  illustrated  with  engravings  and  photo- 
graphs. 

The  working,  practical  operator  will  find  it  a  useful  and  reliable  text-book, 
the  amateur  a  worthy  counselor,  the  lover  of  art  a  valuable  and  beautiful  addi- 
tion to  his  center-table  ;  and  the  artist  will  find  the  landscape  photographs  use- 
ful as  rock,  tree,  and  landscape  studies. 

M.  Carey  Lea,  Esq.,  will  continue  his  valuable  resume  on  "Photography 
Abroad,"  and  contribute  frequent  original  articles.  Mr.  Coleman  Sellers  will 
continue  his  "  Letters  to  an  Engineer  on  Photography,  as  Applied  to  his  Pro- 
fession." Rev.  H.  J.  Morton,  D.  D.,  is  preparing  a  series  of  his  charming 
articles  for  its  pages;  and  occasional  papers  may  be  anticipated  by  Prof. 
Ogden  N.  Rood,  Dr.  R.  Siielton  Mackenzie,  M.  A.  Root,  Esq.,  and  may  other 
well-known  lovers  of  and  co-workers  in  the  art  it  advocates. 

The  Publishers  believe  that  such  a  staff  must  secure  the  publication  of  a 
first-class  Photographic  Journal,  and  ask  the  support  and  influence  of  all  whose 
ideas  substantially  accord  with  theirs  Its  pages  are  open  to  all.  It  is  the 
special  organ  of  the  Philadelphia  Photographic  Society;  but  the  minutes  of 
other  Photographic  Societies  are  requested  from  their  secretaries,  and  will  be 
regularly  published  cheerfully.  The  discussion  or  all  photographic  topics  is 
invited.  'Correspondents  cheerfully  answered  through  its  pages  by  the  Editor. 
The  Photographic  news  of  the  world  regularly  published. 

It  is  gotten  up  in  the  very  best  style,  on  heavy  fine  white  paper,  royal  octavo 
size,  each  number  containing  sixteen  double-column  pages,  in  clear  readable 
type,  and  embellished  with  a  superb  specimen  photograph. 

Subscription,  Three  Dollars  per  annum,  in  advance.  Postage  payable  at  the 
office  where  received.    Single  copies  mailed  on  receipt  of  Thirty  Cents. 

BENERMAN  &  WILSON,  Publishers, 
Office  South-west  Corner  Seventh  and  Cherry  Streets  (Sherman's  Building), 

PHILADELPHIA. 


CHARLES  WALDACK, 

PHOTOGRAPHER. 

ISo.  88  West  Fourth  Street, 

CINCINNATI,  OHIO. 

SPECIALTY  POE  COPYING  AND  ENLAEGING. 
PRICE  LIST 

—  FOR  — 

NL19TIB8  MM  PH0T00RAPHIE8 

ENLARGING  ON  PAINTERS'  CANVAS, 

(PROOFS  PRODUCED  AS  FINE  AS  ON  PAPER.) 


14  by  17  $3  00 

16  by  20   4  00 

18  by  22   5  00 

20  by  24   6  00 

22  by  27   7  00 

25  by  30   8  00 

27  by  34   9  00 

29  by  36....   10  00 

32  by  40  11  00 

34  by  42  !  12  00 

3J  by  4J  feet  14  00 

5    by  7     "   ...  20  00 

THESE  PBIOES  DO  NOT  INCLUDE  THE  CANVAS. 


CHARLES  WALDACK — CONTINUED. 


State  whether  you  want  the  picture  on  smooth,  twilled,  Roman, 
or  Saxon  Canvas. 

All  kinds  of  Negatives,  giving  good  prints  by  contact  printing, 
can,  if  necessary,  be  used  ;  but,  to  produce  the  best  results,  the 
Negative  should  be  made  expressly  for  the  purpose.  It  should 
not  be  larger  than  half  size,  and  should  be  thin,  sharp,  and 
transparent  in  the  shadows.  Avoid  over-exposure.  It  is,  also, 
best  not  to  varnish  it. 

One  Dollar  extra  is  charged  when  a  Negative  has  to  be  made 
of  a  daguerreotype,  photograph,  or  positive  collodion  picture. 

ENLARGING  ON  PAPER. 

The  Prices  are  the  same  as  for  Canvas.— The  same  kind  of 
Negative  is  required. 

I5«UfcEI@I©  NE8AT0VK8, 

COPIED  FROM  DAGUERREOTYPES,  PHOTOGRAPHS,  ETO, 


1-2  size  $1  00 

4-4  size   1  50 

8  by  10   2  00 

10  by  12   2  50 

11  by  14   3  00 

12  by  15     3  50 

14  by  17   4  00 

COPIED  FROM  SMALL  NEGATIVES. 

1-2  size  $2  00 

4-4  size   2  50 

8  by  10   3  00 

10  by  12   3  60 

11  by  14   4  00 

12  by  15     4  50 

14  by  17   5  00 


ASHE,  DAYTON  &  CO. 

ISO   Sc  161  MERCER  STREET, 
NEW  YORK, 

Abe  making  all  kinds  of  Furniture,  Window-Shades,  Backgrounds,  etc.,  at 
the  lowest  prices,  and  of  the  best  quality,  of  the  latest,  new,  and  original 
styles,  both  of  this  country  and  Europe. 

Baekg-rousids. 

Our  Grounds  are  superior  to  any  others,  and  lower  in  price.  We  can  give 
thousands  of  testimonials  from  the  best  Photographers  in  the  country,  Can- 
ada, Cuba,  and  the  West  Indies.  We  make  Scenery  to  a  given  sketch  or 
description,  interior  or  exterior,  park,  landscape,  drawing-room,  boudoir, 
parlor,  etc.,  with  imitation  pillars,  balustrades,  etc.;  and,  being  practical 
Photographers  and  Artists,  can  produce  all  the  effects  requisite  in  a  picture. 
They  are  sold  from  twelve  to  twenty-five  cents  per  superficial  foot,  according 
to  price  of  canvas  and  amount  of  labor  in  the  execution.  Warranted  perfect 
and  unfading  in  color. 

Slcyliglits. 

We  also  mix  for  Skylights  a  fluid  which  we  name  Blue  Frosting,  to  be 
stippled  on  the  glass,  to  prevent  the  sun's  rays  from  passing  through,  giving  a 
blue,  mellow  light.  Sold  in  pint  cans,  which  will  cover  about  one  hundred 
and  twenty  square  feet. 

We  are  making  an  article  called  a  Skylight  Phosgrade,  to  be  hung  under  the 
skylight,  somewhat  in  the  form  of  a  common-window  blind,  of  a  photogenic 
blue  lint,  which  will  graduate  the  light  in  part  or  whole  ;  when  entirely  closed 
will  give  a  good  light  in  the  brightest  day,  but  can  be  graduated  to  any  shade. 
We  have  taken  measures  for  a  Patent.  It  will  be  cheap  and  effective  for  any 
light,  and  can  be  easily  put  up. 

Mock  ITujrnitua-e. 

Our  new  style  of  Furniture  is  from  the  English  and  French.  It  co  rists  of 
various  portions  of  Tables,  Desks,  Bureaus,  Libraries,  etc.  One  piee  of  Fur- 
niture can  be  changed  to  any  configuration,  according  to  the  taste  of  i  e  artist, 
by  joining  the  several  parts  together,  making  a  complete  furnish*  J  room. 

We  solicit  your  favors,  and  feel  confident  we  can  give  satisfacti  a,  having 
had  experience  since  the  birth  of  Photography.  Instructions  give  in  the  art 
for  any  thing  new,  gratis. 

References. 

Fredricks,  Gurney,  Brady,  Lewis,  Thompson,  Kimball,  Bill,  omington, 
Kertson,  Percival,  Adams, 'Holmes,  Morse,  Farris,  Johnson  Broo  Hoot,  and 
others,  New  York;  Benden  Bros.,  Baltimore;  Germon,  Guteku':  it,  Philadel- 
phia; Bennet,  Gordon,  Benjamin,  Washington,  D.  C. ;  Howe,  T<**»,  Vermont; 
Coner,  Cuba  ;  Clarke,  Victor,  Peard,  New  Jersey;  Davis,  Bill,  Prescot  &  Gage, 
Hartford;  Moulthrop  &  Williams,  New  Havem  Connecticut;  Silsbee,  Case  & 
Co.,  Boston,  Massachusetts,  and  others — in  fact,  all  the  best  Photographers 
in  the  country. 

Important  Notice. 

We  have  made  arrangements  with  the  Patentee,  in  England,  for  an  impor- 
tation of  ten  thousand  dollars'  worth  of  a  new  manufacture  of  plain  Back- 
grounds made  of  woolen  cloth;  will  last  forever  and  never  fade  ;  can  not  be 
injured  by  water  or  rubbing;  can  be  sent  in  a  small  parcel  to  any  distance 
without  injury.  Will  be  sold  by  all  Stock  Dealers.  We  shall  give  notice  on 
the  receipt  of  them.  The  shades  of  the  Grounds  will  be  the  same  as  the  num- 
bers we  have  sold  these  ten  years — from  1  to  10.  These  Grounds  will  be  far 
superior  to  oil  grounds,  distemper,  felt,  sanded,  or  any  other;  for  having  made 
all  of  them  ourselves,  during  twenty  years  experience  in  daguerreotype,  am- 
brotype,  and  photography  in  general,  we  can,  most  assuredly,  recommend 
them,  as  one  of  our  firm  has  proved  them.    Wait  awhile. 

ASHE,   DAYTON"  &c  CO., 

159  &  161  Mercer  Street,  N.  Y. 


BIST  GOODS!  LARGEST  STOCK!!  LOWEST  PRICES  I ! ! 


J.  V.  ESCOTT, 

^inmxfnttnzez,  ||mptrrt*r,  tmir  JmUr 

 IN  

PHOTOGRAPHIC  AND  AMBR0TYP1 

APPARATUS. 

Cases,  Glass, 
Mattings,  Chemicals, 
Preservers,     Back  Grounds,    Card  Mounts, 
Photographic  Albums, 
Gilt  and  Rosewood  Frames, 
PLAIN  AND  ALBUMEN  PAPER, 

J.  V.  ESCOTT'S  STAR  PLATE, 

AND  EVERT  DESCRIPTION  OF  GOODS  USED  IN  THE  BUSINESS, 

Agent  for  Mowry's  (Sibley  Patent)  Presses. 

CARD  MOUNTS  PRINTED  ON  THE  PREMISES. 

All   Orders    Promptly  Attended  to. 

J".  V.  ESCOTT, 

Depot,  231  Main  Street.        Factory,  First  Street. 
LOUISVILLE,  KY. 


I 


